Comprehensive Physiology Wiley Online Library

Facilitated Diffusion of Oxygen and Carbon Dioxide

Full Article on Wiley Online Library



Abstract

The sections in this article are:

1 Facilitated Diffusion of O2
1.1 Experimental Basis
1.2 Molecular Mechanism
1.3 Quantitative Interpretation
1.4 Diffusion Coefficients of O2 and Hemoglobin
1.5 Facilitated Diffusion of CO
1.6 Facilitated O2 Diffusion in Non‐Steady‐State Oxygenation
1.7 Physiological Significance of Facilitated O2 Diffusion
2 Facilitated Diffusion of CO2
2.1 Theory
2.2 Experimental Studies
2.3 Physiological Significance
Figure 1. Figure 1.

Basic characteristics of facilitated diffusion of O2. Upper panel, steady‐state O2 fluxes (μl/min) through layer of Hb solution vs. partial pressure of O2 () at chemical equilibrium in absence of back pressure at low‐pressure side. Millipore membrane 150 μm, Hb concentration 19 g/100 ml, temperature 25°C. ↔, Plain diffusion component (Hb inactivated as metHb, ‐ ‐ ‐ ‐ ‐) of total O2 flux (‐ ‐ ‐), ↔, Hb‐augmented component. In ascending part of facilitated flux, 2 curves reflect 2 HbO2 dissociation curves, pH 7.3 and 6.0. Lower panel, dimensionless relative facilitation (Fac): (total flux — plain flux)/plain flux = facilitated flux/plain flux vs. . Maximum facilitation ∼8 at pH 7.3 and ∼3 at pH 6.0. Maximum at pH 7.3 occurs at lower than at pH 6.0, due to respective position of HbO2 dissociation curve. Two curves do not pass through origin where quotient mentioned above is 0/0 or undefined.

Upper panel adapted from Hemmingsen 68 and Wittenberg 198
Figure 2. Figure 2.

Regions where approximate analytic solutions can be obtained (for one reaction and one permeant S), depending on concentration difference ΔS, equilibrium (association) constant K, and Damköhler number γ. Two extreme asymptotic regimes are hatched (left, near‐diffusion regime; right, near‐equilibrium regime).

From Schultz et al. 157
Figure 3. Figure 3.

Profiles of O2 pressure (, bottom), O2 saturation (Sat, top), and nonequilibrium facilitation (Fac,.….) plotted against distance (x) in 5‐μm‐thick layer of 15 g/100 ml Mb solution at steady state, exposed to of 10 (left) and 0 (right) Torr. Curves are scaled for same flux contribution. Saturation scale only covers range from 75% to 100%. _____, Calculated profiles for nonequilibrium 76,102; at boundaries, slopes are equal (steady state) and slopes of MbO2 saturation are 0 (no flux). ‐ ‐ ‐ ‐ ‐, Equilibrium core extensions. ‐ ‐ ‐ ‐ ‐, Profiles for equilibrium presumed throughout layer. Top, ‐ ‐ ‐ ‐ ‐: saturation starts at equilibrium value of <100% because a of 10 Torr is not sufficient for complete saturation and would continue to 0 on right side. , Penetration depth λ for nonequilibrium 39; although this penetration depth is smaller at low‐pressure boundary, its effect of raising the MbO2 saturation is enormous (from 0% at equilibrium to 77% at nonequilibrium) due to steep course of MbO2 dissociation curve in this range.

Figure 4. Figure 4.

Comparison of various approximate analytic approaches to describe facilitated diffusion in plot of facilitation (Fac) against layer thickness L and Damköhler number γ. Calculations for Hb solution of 15 g/100 ml and difference of 200 vs. 2 Torr to compare with numerical results (•) of Kutchai et al. 109.‐ ‐ ‐ ‐ ‐, Asymptotes; near‐diffusion asymptote (left) coincides with thin‐layer first‐order solution 161 and near‐equilibrium asymptote (top) corresponds with thick‐layer zero‐order solutions (maximum facilitation). Lines and ‐ ‐ ‐ ‐ ‐ (approximate formulas) indicate the solutions: 1, weak boundary layer, first order 46,130; 2, weak boundary layer, second order 46,152; 3, strong boundary layer 101; 4, strong boundary layer 102; 5, thick layer, first order 161; 6, thick layer, second order 161; 7, thin layer, second order 161; 8, slow reaction 189; 9, single‐point linearization 39,46; 10, wide range, improved for flat layers 76; 11, interpolation formula, modified for nonzero back pressure 203; see ref. 160 for similar solution; 12, approximation for sufficiently thick layers 161.

Figure 5. Figure 5.

Curve of diffusion coefficient of O2 (, top) from Gold‐stick and Fatt 48 and Kreuzer 100 and values of DHb obtained by various authors as a function of Hb concentration at 25°C. Symbols, tracer DHb, (Dt, except •): □, Keller and Friedlander 92, pH 7.4; ▪, Moll 132; ○, Adams and Fatt 1; •, Keller et al. 90, mutual Dm, pH 7.3; , Keller et al. 90, tracer Dt, pH 7.3; Δ, Riveros‐Moreno and Wittenberg 149, pH 7.3; ▴, Gros 51, pH 7.2, ionic strength I = 150 mM; ×, Spaan et al. 164. Numbered lines, mutual DHb, (Dm): 1, Wilson et al. 193, pH 7.0; 2, Alpert and Banks 2, pH 7.0, I = 100 mM; 3, Veldkamp and Votano 185, pH 7.2, I = 125 mM; 4, Jones et al. 81, pH 6.9 = isoelectric point IP, I = 100 mM; 5, Hall et al. 63, pH 6.7 = IP of deoxy Hb, I = 200 mM; 6, LaGattuta et al. 115, pH 6.9, I = 150 mM; ‐ ‐ ‐ ‐ ‐, Dt, calculated from Dm according to Hall et al. 63 up to 16 g/100 ml;.…., Dt calculated from Dm 63 extrapolated up to 35 g/100 ml;.…., Dt calculated from Stokes‐Einstein equation according to Equation 1 in Young et al. 202 with values of viscosity coefficient obtained by Kreuzer 99.

Figure 6. Figure 6.

Schematic profiles of species important in facilitated CO2 diffusion across a layer. Conditions assumed: , difference from 45 Torr (x = 0) to 15 Torr (x = L); mean concentrations: Na+ = 150 mM, Cl = 130 mM (not bound to Hb), Hb = 5 mM. Temperature, 21°C. Values at upper (x = 0) vs. lower (x = L) boundary.‐ ‐ ‐, With potential;‐ ‐ ‐ ‐, without potential.

With Potential

Without Potential

Parameter

45 Torr

15 Torr

45 Torr

15 Torr

Na+, mM

146.6

154.4

150

150

Cl, mM

133.0

126.3

130

130

, mM

17.7

16.1

21.1

12.2

, mM1

0.03

0.07

0.04

0.04

pH

7.09

7.53

7.17

7.41

Hb, mM

5.02

4.82

5

5

Facilitation (Fac)

0.322

4.32

CO2, mM

2.00

0.67

2.00

0.67

Charge of Hb (zHb)

+0.8

‐2.5

+0.2

‐1.6

Potential (U), mV

0

‐1.3

0

Not shown on figure.

Mean values over the whole layer.

.

according to De Koning et al. 24


Figure 1.

Basic characteristics of facilitated diffusion of O2. Upper panel, steady‐state O2 fluxes (μl/min) through layer of Hb solution vs. partial pressure of O2 () at chemical equilibrium in absence of back pressure at low‐pressure side. Millipore membrane 150 μm, Hb concentration 19 g/100 ml, temperature 25°C. ↔, Plain diffusion component (Hb inactivated as metHb, ‐ ‐ ‐ ‐ ‐) of total O2 flux (‐ ‐ ‐), ↔, Hb‐augmented component. In ascending part of facilitated flux, 2 curves reflect 2 HbO2 dissociation curves, pH 7.3 and 6.0. Lower panel, dimensionless relative facilitation (Fac): (total flux — plain flux)/plain flux = facilitated flux/plain flux vs. . Maximum facilitation ∼8 at pH 7.3 and ∼3 at pH 6.0. Maximum at pH 7.3 occurs at lower than at pH 6.0, due to respective position of HbO2 dissociation curve. Two curves do not pass through origin where quotient mentioned above is 0/0 or undefined.

Upper panel adapted from Hemmingsen 68 and Wittenberg 198


Figure 2.

Regions where approximate analytic solutions can be obtained (for one reaction and one permeant S), depending on concentration difference ΔS, equilibrium (association) constant K, and Damköhler number γ. Two extreme asymptotic regimes are hatched (left, near‐diffusion regime; right, near‐equilibrium regime).

From Schultz et al. 157


Figure 3.

Profiles of O2 pressure (, bottom), O2 saturation (Sat, top), and nonequilibrium facilitation (Fac,.….) plotted against distance (x) in 5‐μm‐thick layer of 15 g/100 ml Mb solution at steady state, exposed to of 10 (left) and 0 (right) Torr. Curves are scaled for same flux contribution. Saturation scale only covers range from 75% to 100%. _____, Calculated profiles for nonequilibrium 76,102; at boundaries, slopes are equal (steady state) and slopes of MbO2 saturation are 0 (no flux). ‐ ‐ ‐ ‐ ‐, Equilibrium core extensions. ‐ ‐ ‐ ‐ ‐, Profiles for equilibrium presumed throughout layer. Top, ‐ ‐ ‐ ‐ ‐: saturation starts at equilibrium value of <100% because a of 10 Torr is not sufficient for complete saturation and would continue to 0 on right side. , Penetration depth λ for nonequilibrium 39; although this penetration depth is smaller at low‐pressure boundary, its effect of raising the MbO2 saturation is enormous (from 0% at equilibrium to 77% at nonequilibrium) due to steep course of MbO2 dissociation curve in this range.



Figure 4.

Comparison of various approximate analytic approaches to describe facilitated diffusion in plot of facilitation (Fac) against layer thickness L and Damköhler number γ. Calculations for Hb solution of 15 g/100 ml and difference of 200 vs. 2 Torr to compare with numerical results (•) of Kutchai et al. 109.‐ ‐ ‐ ‐ ‐, Asymptotes; near‐diffusion asymptote (left) coincides with thin‐layer first‐order solution 161 and near‐equilibrium asymptote (top) corresponds with thick‐layer zero‐order solutions (maximum facilitation). Lines and ‐ ‐ ‐ ‐ ‐ (approximate formulas) indicate the solutions: 1, weak boundary layer, first order 46,130; 2, weak boundary layer, second order 46,152; 3, strong boundary layer 101; 4, strong boundary layer 102; 5, thick layer, first order 161; 6, thick layer, second order 161; 7, thin layer, second order 161; 8, slow reaction 189; 9, single‐point linearization 39,46; 10, wide range, improved for flat layers 76; 11, interpolation formula, modified for nonzero back pressure 203; see ref. 160 for similar solution; 12, approximation for sufficiently thick layers 161.



Figure 5.

Curve of diffusion coefficient of O2 (, top) from Gold‐stick and Fatt 48 and Kreuzer 100 and values of DHb obtained by various authors as a function of Hb concentration at 25°C. Symbols, tracer DHb, (Dt, except •): □, Keller and Friedlander 92, pH 7.4; ▪, Moll 132; ○, Adams and Fatt 1; •, Keller et al. 90, mutual Dm, pH 7.3; , Keller et al. 90, tracer Dt, pH 7.3; Δ, Riveros‐Moreno and Wittenberg 149, pH 7.3; ▴, Gros 51, pH 7.2, ionic strength I = 150 mM; ×, Spaan et al. 164. Numbered lines, mutual DHb, (Dm): 1, Wilson et al. 193, pH 7.0; 2, Alpert and Banks 2, pH 7.0, I = 100 mM; 3, Veldkamp and Votano 185, pH 7.2, I = 125 mM; 4, Jones et al. 81, pH 6.9 = isoelectric point IP, I = 100 mM; 5, Hall et al. 63, pH 6.7 = IP of deoxy Hb, I = 200 mM; 6, LaGattuta et al. 115, pH 6.9, I = 150 mM; ‐ ‐ ‐ ‐ ‐, Dt, calculated from Dm according to Hall et al. 63 up to 16 g/100 ml;.…., Dt calculated from Dm 63 extrapolated up to 35 g/100 ml;.…., Dt calculated from Stokes‐Einstein equation according to Equation 1 in Young et al. 202 with values of viscosity coefficient obtained by Kreuzer 99.



Figure 6.

Schematic profiles of species important in facilitated CO2 diffusion across a layer. Conditions assumed: , difference from 45 Torr (x = 0) to 15 Torr (x = L); mean concentrations: Na+ = 150 mM, Cl = 130 mM (not bound to Hb), Hb = 5 mM. Temperature, 21°C. Values at upper (x = 0) vs. lower (x = L) boundary.‐ ‐ ‐, With potential;‐ ‐ ‐ ‐, without potential.

With Potential

Without Potential

Parameter

45 Torr

15 Torr

45 Torr

15 Torr

Na+, mM

146.6

154.4

150

150

Cl, mM

133.0

126.3

130

130

, mM

17.7

16.1

21.1

12.2

, mM1

0.03

0.07

0.04

0.04

pH

7.09

7.53

7.17

7.41

Hb, mM

5.02

4.82

5

5

Facilitation (Fac)

0.322

4.32

CO2, mM

2.00

0.67

2.00

0.67

Charge of Hb (zHb)

+0.8

‐2.5

+0.2

‐1.6

Potential (U), mV

0

‐1.3

0

Not shown on figure.

Mean values over the whole layer.

.

according to De Koning et al. 24
References
 1. Adams, L. R., and I. Fatt. The diffusion coefficient of human hemoglobin at high concentrations. Respir. Physiol. 2: 293–301, 1967.
 2. Alpert, S. S., and G. Banks. The concentration dependence of the hemoglobin mutual diffusion coefficient. Biophys. Chem. 4: 287–296, 1976.
 3. Antonini, E., M. Brunori, B. Giardina, P. A. Benedetti, and N. Pintus. Kinetics of oxygen reactions within single erythrocytes. Observation by microspectrophotometry. In: Hemoglobin and Oxygen Binding, edited by C. Ho. New York: Elsevier/North‐Holland, 1982, p. 449–452.
 4. Araki, R., M. Tamura, and I. Yamazaki. The effect of intracellular oxygen concentration on lactate release, pyridine nucleotide reduction and respiration rate in the rat cardiac tissue. Circ. Res. 53: 448–455, 1983.
 5. Barlow, C. H., B. Chance, W. Harden III, M. B. Simson, and A. H. Harken. Spectroscopic mapping of oxygen supply‐demand in heart. In: Biochemical and Clinical Aspects of Oxygen, edited by W. S. Caughey. New York: Academic, 1979, p. 845–856.
 6. Batchelor, G. K. Brownian diffusion of particles with hydrodynamic interaction. J. Fluid Mech. 74: 1–29, 1976.
 7. Bright, P. B. The basic flow equations of electrophysiology in the presence of chemical reactions. II. A practical application concerning the pH and voltage effects accompanying the diffusion of O2 through hemoglobin solution. Bull. Math. Biophys. 29: 123–138, 1967.
 8. Britton, N. F., and J. D. Murray. The effect of carbon monoxide on haem‐facilitated oxygen diffusion. Biophys. Chem. 7: 159–167, 1977.
 9. Broun, G., E. Selegny, C. Tran Minh, and D. Thomas. Facilitated transport of CO2 across a membrane bearing carbonic anhydrase. FEBS Lett. 7: 223–226, 1970.
 10. Burns, B., and G. H. Gurtner. A specific carrier for oxygen and carbon monoxide in the lung and placenta. Drug Metab. Dispos. 1: 374–379, 1973.
 11. Burns, B., and R. H. Shepard. DlO2 in excised lungs perfused with blood containing sodium dithionite (Na2S2O4). J. Appl. Physiol. 46: 100–110, 1979.
 12. Burns, B., and R. H. Shepard. Membrane diffusion. Comparison between dithionite DO2 and DLCO. Prog. Respir. Res. 16: 130–141, 1981.
 13. Chance, B., and B. Quistorff. Study of tissue oxygen gradients by single and multiple indicators. Adv. Exp. Med. Biol. 94: 331–338, 1978.
 14. Clark, A., Jr., and P. A. A. Clark. Local oxygen gradients near mitochondria in tissue. Microvasc. Res. 29: 212–213, 1985.
 15. Clark, A., Jr., G. R. Cokelet, and W. J. Federspiel. Erythrocyte motion and oxygen transport. Bibl. Anat. 20: 385–388, 1981.
 16. Clark, A., Jr., W. J. Federspiel, P. A. A. Clark, and G. R. Cokelet. Oxygen delivery from red cells. Biophys. J. 47: 171–181, 1985.
 17. Cole, R. P. Myoglobin function in exercising skeletal muscle. Science Wash. DC 216: 523–525, 1982.
 18. Cole, R. P. Skeletal muscle function in hypoxia. Effect of alteration of intracellular myoglobin. Respir. Physiol. 53: 1–14, 1983.
 19. Cole, R. P., P. C. Sukanek, J. B. Wittenberg, and B. A. Wittenberg. Mitochondrial function in the presence of myoglobin. J. Appl. Physiol. 53: 1116–1124, 1982.
 20. Cole, R. P., B. A. Wittenberg, and P. R. B. Caldwell. Myoglobin function in the isolated fluorocarbon‐perfused dog heart. Am. J. Physiol. 234 (Heart Circ. Physiol. 3): H567–H572, 1978.
 21. Colton, C. K., P. Stroeve, and J. G. Zahka. Mechanism of oxygen transport augmentation by hemoglobin. J. Appl. Physiol. 35: 307–309, 1973.
 22. Connett, R. J., T. E. J. Gayeski, and C. R. Honig. Lactate accumulation in fully aerobic, working, dog gracilis muscle. Am. J. Physiol. 246 (Heart Circ. Physiol. 15): H120–H128, 1984.
 23. De Koning, J., L. J. C. Hoofd, and F. Kreuzer. Oxygen transport and the function of myoglobin. Theoretical model and experiments in chicken gizzard smooth muscle. Pfluegers Arch. 389: 211–217, 1981.
 24. De Koning, J., P. Stroeve, and J. H. Meldon. Electrical potentials during carbon dioxide transport in hemoglobin solutions. Adv. Exp. Med. Biol. 94: 183–188, 1978.
 25. Diller, T. E., and B. B. Mikic. Modeling the oxygen diffusion effects of red cell motions in flowing blood. In: Advances in Bioengineering, edited by V. C. Mow. New York: Am. Soc. Mech. Eng., 1980, p. 177–180.
 26. Diller, T. E., and I. A. Pattantyus. Analytical modeling of facilitated transport in flowing hemoglobin solutions. In: Advances in Bioengineering, edited by D. L. Bartel. New York: Am. Soc. Mech. Eng., 1983, p. 7–8.
 27. Donaldson, T. T., and J. A. Quinn. Kinetic constants determined from membrane transport measurements. Carbonic anhydrase activity at high concentrations. Proc. Natl. Acad. Sci. USA 71: 4995–4999, 1974.
 28. Driedzic, W. R. The fish heart as a model system for the study of myoglobin. Comp. Biochem. Physiol. A Comp. Physiol. 76: 487–493, 1983.
 29. Driedzic, W. R., J. M. Stewart, and D. L. Scott. The protective effect of myoglobin during hypoxic perfusion of isolated fish hearts. J. Mol. Cell. Cardiol. 14: 673–677, 1982.
 30. Engasser, J.‐M. A fast evaluation of diffusion effects on bound enzyme activity. Biochim. Biophys. Acta 526: 301–310, 1978.
 31. Engasser, J.‐M., and C. Horvath. Buffer‐facilitated proton transport. pH Profile of bound enzymes. Biochim. Biophys. Acta 358: 178–192, 1974.
 32. Enns, T. Molecular collision‐exchange transport of oxygen by hemoglobin. Proc. Natl. Acad. Sci. USA 51: 247–252, 1964.
 33. Enns, T. Carbonic anhydrase facilitated transport of CO2 (Abstract). Federation Proc. 24: 397, 1965.
 34. Federspiel, W. J. The effect of myoglobin concentration on muscle cell PO2 gradients. Adv. Exp. Med. Biol. 180: 539–543, 1984.
 35. Figulla, H. R., J. Hoffmann, and D. W. Lübbers. Coronary conductivity and tissue oxygenation as measured by the myoglobin O2 saturation and the cytochrome aa3 redox state in the Langendorff guinea pig heart preparation. Adv. Exp. Med. Biol. 159: 579–585, 1983.
 36. Fletcher, J. E. On facilitated oxygen diffusion in muscle tissue. Biophys. J. 29: 437–458, 1980.
 37. Folkner, C. A., and R. D. Noble. Transient response of facilitated transport membranes. J. Membr. Sci. 12: 289–301, 1983.
 38. Fox, M. A., and H. D. Landahl. Theory of hemoglobin facilitated oxygen transport. Bull. Math. Biophys. 27: 183–190, 1965.
 39. Friedlander, S. K., and K. H. Keller. Mass transfer in reacting systems near equilibrium. Use of the affinity function. Chem. Eng. Sci. 20: 121–129, 1965.
 40. Gayeski, T. E. J., R. J. Connett, and C. R. Honig. Oxygen transport in the rest‐work transition illustrates new functions for myoglobin. Am. J. Physiol. 248 (Heart Circ. Physiol. 17): H914–H921, 1985.
 41. Gayeski, T. E. J., and C. R. Honig. Myoglobin saturation and calculated PO2 in single cells of resting gracilis muscles. Adv. Exp. Med. Biol. 94: 77–84, 1978.
 42. Gayeski, T. E. J., and C. R. Honig. Direct measurement of intracellular O2 gradients; role of convection and myoglobin. Adv. Exp. Med. Biol. 159: 613–621, 1983.
 43. Gijsbers, G. H., and H. J. van Ouwerkerk. Boundary layer resistance of steady‐state oxygen diffusion facilitated by a four‐step chemical reaction with hemoglobin in solution. Pfluegers Arch. 365: 231–241, 1976.
 44. Goddard, J. D. Further applications of carrier‐mediated transport theory—a survey. Chem. Eng. Sci. 32: 795–809, 1977.
 45. Goddard, J. D. A model of facilitated transport in concentrated two‐phase dispersions. Chem. Eng. Commun. 9: 345–361, 1981.
 46. Goddard, J. D., J. S. Schultz, and R. J. Bassett. On membrane diffusion with near‐equilibrium reaction. Chem. Eng. Sci. 25: 665–683, 1970.
 47. Goddard, J. D., J. S. Schultz, and S. R. Suchdeo. Facilitated transport via carrier‐mediated diffusion in membranes. Pt. III. Mathematical aspects and analyses. AIChE J. 20: 625–645, 1974.
 48. Goldstick, T. K., and I. Fatt. Diffusion of oxygen in solutions of blood proteins. Chem. Eng. Prog. Symp. Series 66: 101–113, 1970.
 49. Gonzalez‐Fernandez, J. M., and S. E. Atta. Transport of oxygen in solutions of hemoglobin and myoglobin. Math. Biosci. 54: 265–290, 1981.
 50. Gonzalez‐Fernandez, J. M., and S. E. Atta. Facilitated transport of oxygen in the presence of membranes in the diffusion path. Biophys. J. 38: 133–141, 1982.
 51. Gros, G. Concentration dependence of the self‐diffusion of human and Lumbricus terrestris hemoglobin. Biophys. J. 22: 453–468, 1978.
 52. Gros, G., F. Ganghoff, P. Scheid, W. Siffert, W. Teske, and D. Krüger. Concentration, properties, and functional significance of skeletal muscle carbonic anhydrase III. Pfluegers Arch. 400, Suppl.: R58, 1984.
 53. Gros, G., H. Gros, D. Lavalette, B. Amand, and F. Pochon. Mechanisms of facilitated CO2 and H+ diffusion in protein solutions. In: Biophysics and Physiology of Carbon Dioxide, edited by C. Bauer, G. Gros, and H. Bartels. Berlin: Springer‐Verlag, 1980, p. 36–48. (Symp. Univ. Regensburg, April 17–20, 1979.)
 54. Gros, G., D. Lavalette, W. Moll, H. Gros, B. Amand, and F. Pochon. Evidence for rotational contribution to protein‐facilitated proton transport. Proc. Natl. Acad. Sci. USA 81: 1710–1714, 1984.
 55. Gros, G., and W. Moll. The diffusion of carbon dioxide in erythrocytes and hemoglobin solutions. Pfluegers Arch. 324: 249–266, 1971.
 56. Gros, G., and W. Moll. Facilitated diffusion of CO2 across albumin solutions. J. Gen. Physiol. 64: 356–371, 1974.
 57. Gros, G., W. Moll, H. Hoppe, and H. Gros. Proton transport by phosphate diffusion—a mechanism of facilitated CO2 transfer. J. Gen. Physiol. 67: 773–790, 1976.
 58. Gurtner, G. H., and B. Burns. Possible facilitated transport of oxygen across the placenta. Nature Lond. 240: 473–475, 1972.
 59. Gurtner, G. H., and H. H. Peavy. Evidence for facilitated transport of O2 and CO in the lungs. Prog. Respir. Res. 16: 161–165, 1981.
 60. Gutknecht, J., and D. C. Tosteson. Diffusion of weak acids across lipid bilayer membranes: effects of chemical reactions in the unstirred layers. Science Wash. DC 182: 1258–1261, 1973.
 61. Haas, D. D., and B. R. Ware. Electrophoretic mobilities and diffusion coefficients of hemoglobin at high pH. Biochemistry 17: 4946–4950, 1978.
 62. Hall, R. S., and C. S. Johnson, Jr. Experimental evidence that mutual and tracer diffusion coefficients for hemoglobin are not equal. J. Chem. Phys. 72: 4251–4253, 1980.
 63. Hall, R. S., Y. S. Oh, and C. S. Johnson, Jr. Photon correlation spectroscopy in strongly absorbing and concentrated samples with applications to unliganded hemoglobin. J. Phys. Chem. 84: 756–767, 1980.
 64. Hanna, R. E., and J. B. Garner. An analysis of facilitated‐diffusion problems. Math. Biosci. 63: 9–20, 1983.
 65. Hassinen, I. E., J. K. Hiltunen, and T. E. S. Takala. Reflectance spectrophotometric monitoring of the isolated perfused heart as a method of measuring the oxidation‐reduction state of cytochromes and oxygenation of myoglobin. Cardiovasc. Res. 15: 86–91, 1981.
 66. Hellums, J. D. The resistance to oxygen transport in the capillaries relative to that in the surrounding tissue. Microvasc. Res. 13: 131–136, 1977.
 67. Hemmingsen, E. A. Enhancement of oxygen transport by myoglobin. Comp. Biochem. Physiol. 10: 239–244, 1963.
 68. Hemmingsen, E. A. Accelerated transfer of oxygen through solutions of heme pigments. Acta Physiol. Scand. Suppl. 246: 1–53, 1965.
 69. Hemmingsen, E., and P. F. Scholander. Specific transport of oxygen through hemoglobin solutions. Science Wash. DC 132: 1379–1381, 1960.
 70. Hill, E. P., and T. Enns. CO2 diffusing capacity in isolated lungs. Prog. Respir. Res. 16: 172–176, 1981.
 71. Hills, B. A. Chemical facilitation of gas transfer liquids. Br. Chem. Eng. 16: 175–177, 1971.
 72. Honig, C. R., M. L. Feldstein, and J. L. Frierson. Capillary lengths, anastomoses, and estimated capillary transit times in skeletal muscle. Am. J. Physiol. 233 (Heart Circ. Physiol. 2): H122–H129, 1977.
 73. Honig, C. R., T. E. J. Gayeski, W. Federspiel, A. Clark, Jr., and P. Clark. Muscle O2 gradients from hemoglobin to cytochrome: new concepts, new complexities. Adv. Exp. Med. Biol. 169: 23–38, 1984.
 74. Hoofd, L., P. Breepoel, and F. Kreuzer. Facilitated diffusion and electrical potentials in protein solutions with ionic species. Adv. Exp. Med. Biol. 169: 133–143, 1984.
 75. Hoofd, L., and F. Kreuzer. Calculation of the facilitation of O2 or CO transport by Hb or Mb by means of a new method for solving the carrier‐diffusion problem. Adv. Exp. Med. Biol. 94: 163–168, 1978.
 76. Hoofd, L., and F. Kreuzer. A new mathematical approach for solving carrier‐facilitated steady‐state diffusion problems. J. Math. Biol. 8: 1–13, 1979.
 77. Hoofd, L., and F. Kreuzer. The mathematical treatment of steady state diffusion of reacting species. AIChE Symp. Ser. 77: 123–129, 1981.
 78. Hoofd, L., and A. Lamboo. Oxygen permeability of methemoglobin solutions soaked in Millipore filters. Adv. Exp. Med. Biol. 191: 565–570, 1985.
 79. Jacquez, J. A. The physiological role of myoglobin: more than a problem in reaction‐diffusion kinetics. Math. Biosci. 68: 57–97, 1984.
 80. Jacquez, J. A., H. Kutchai, and E. Daniels. Hemoglobin‐facilitated diffusion of oxygen: interfacial and thickness effects. Respir. Physiol. 15: 166–181, 1972.
 81. Jones, C. R., C. S. Johnson, Jr., and J. T. Penniston. Photon correlation spectroscopy of hemoglobin: diffusion of oxy‐Hba and oxy‐HbS. Biopolymers 17: 1581–1593, 1978.
 82. Jones, D. P. Intracellular O2 gradients—detection at the outer mitochondrial membrane by monoamine oxidase activity (Abstract). Federation Proc. 42: 994, 1983.
 83. Jones, D. P., and F. G. Kennedy. Intracellular O2 gradients in cardiac myocytes. Lack of a role for myoglobin in facilitation of intracellular O2 diffusion. Biochem. Biophys. Res. Commun. 105: 419–424, 1982.
 84. Jones, D. P., and F. G. Kennedy. Intracellular oxygen supply during hypoxia. Am. J. Physiol. 243 (Cell Physiol. 12): C247–C253, 1982.
 85. Jones, D. P., and H. S. Mason. Gradients of O2 concentration in hepatocytes. J. Biol. Chem. 253: 4874–4880, 1978.
 86. Jones, H. A., P. D. Buckingham, J. C. Clark, R. E. Forster, J. D. Heather, J. M. B. Hughes, and C. G. Rhodes. Constant rate of CO uptake with variable inspired CO concentration. Prog. Respir. Res. 16: 169–171, 1981.
 87. Katz, I. R., J. B. Wittenberg, and B. A. Wittenberg. Monoamine oxidase, an intracellular probe of oxygen pressure in isolated cardiac myocytes. J. Biol. Chem. 259: 7504–7509, 1984.
 88. Kawashiro, T., J. Piiper, and P. Scheid. Dependence of O2 uptake on surface PO2 in intact, excised skeletal muscle of the rat: validity of the Warburg model (Abstract). J. Physiol. Lond. 284: 45P–46P, 1978.
 89. Kawashiro, T., and P. Scheid. Measurement of Krogh's diffusion constant of CO2 in respiring muscle at various CO2 levels: evidence for facilitated diffusion. Pfluegers Arch. 362: 127–133, 1976.
 90. Keller, K. H., E. R. Canales, and S. I. Yum. Tracer and mutual diffusion coefficients of proteins. J. Phys. Chem. 75: 379–387, 1971.
 91. Keller, K. H., and S. K. Friedlander. The steady‐state transport of oxygen through hemoglobin solutions. J. Gen. Physiol. 49: 663–679, 1966.
 92. Keller, K. H., and S. K. Friedlander. Diffusivity measurements of human methemoglobin. J. Gen. Physiol. 49: 681–687, 1966.
 93. Kemena, L. L., R. D. Noble, and N. J. Kemp. Optimal regimes of facilitated transport. J. Membr. Sci. 15: 259–274, 1983.
 94. Kemp, N. J., and R. D. Noble. Heat transfer effects in facilitated transport liquid membranes. Sep. Sci. Technol. 18: 1147–1165, 1983.
 95. Kitchen, R. G., B. N. Preston, and J. D. Wells. Diffusion and sedimentation of serum albumin in concentrated solutions. J. Polym. Sci. Polym. Symp. 55: 39–49, 1976.
 96. Klug, A., F. Kreuzer, and F. J. W. Roughton. The diffusion of oxygen in concentrated haemoglobin solutions. Helv. Physiol. Pharmacol. Acta 14: 121–128, 1956.
 97. Klug, A., F. Kreuzer, and F. J. W. Roughton. Simultaneous diffusion and chemical reaction in thin layers of haemoglobin solution. Proc. R. Soc. Lond. B Biol. Sci. 145: 452–472, 1956.
 98. Kolkka, R. W., and E. P. Salathé. A mathematical analysis of carrier‐facilitated diffusion. Math. Biosci. 71: 147–180, 1984.
 99. Kreuzer, F. Modellversuche zum Problem der Sauerstoffdiffusion in den Lungen. Helv. Physiol. Pharmacol. Acta 11, Suppl. 9: 1–99, 1953.
 100. Kreuzer, F. Facilitated diffusion of oxygen and its possible significance; a review. Respir. Physiol. 9: 1–30, 1970.
 101. Kreuzer, F., and L. J. C. Hoofd. Facilitated diffusion of oxygen in the presence of hemoglobin. Respir. Physiol. 8: 280–302, 1970.
 102. Kreuzer, F., and L. J. C. Hoofd. Factors influencing facilitated diffusion of oxygen in the presence of hemoglobin and myoglobin. Respir. Physiol. 15: 104–124, 1972.
 103. Kreuzer, F., and L. J. C. Hoofd. Facilitated diffusion of CO and oxygen in the presence of hemoglobin or myoglobin. Adv. Exp. Med. Biol. 75: 207–215, 1976.
 104. Kreuzer, F., and L. Hoofd. Facilitated diffusion of oxygen: possible significance in blood and muscle. Adv. Exp. Med. Biol. 169: 3–21, 1984.
 105. Kreuzer, F., and W. Z. Yahr. Influence of red cell membrane on diffusion of oxygen. J. Appl. Physiol. 15: 1117–1122, 1960.
 106. Kutchai, H. Numerical study of oxygen uptake by layers of hemoglobin solution. Respir. Physiol. 10: 273–284, 1970.
 107. Kutchai, H. O2 uptake by 100 μ layers of hemoglobin solution. Theory vs. experiment. Respir. Physiol. 11: 378–383, 1971.
 108. Kutchai, H. Wider applicability for Hill's advancing front theory of oxygen uptake. J. Appl. Physiol. 31: 302–304, 1971.
 109. Kutchai, H., J. A. Jacquez, and F. J. Mather. Nonequilibrium facilitated oxygen transport in hemoglobin solution. Biophys. J. 10: 38–54, 1970.
 110. Kutchai, H., and N. C. Staub. Steady‐state, hemoglobin‐facilitated O2 transport in human erythrocytes. J. Gen. Physiol. 53: 576–589, 1969.
 111. La Force, R. C. Steady‐state diffusion in the carbon monoxide + oxygen + hemoglobin system. Trans. Faraday Soc. 62: 1458–1468, 1966.
 112. La Force, R. C., and I. Fatt. Steady‐state diffusion of oxygen through whole blood. Trans. Faraday Soc. 58: 1451–1464, 1962.
 113. La Force, R. C., and I. Fatt. Steady‐state gas transport through hemoglobin solutions. Biopolym. Symp. 1: 555–562, 1964.
 114. La Force, R. C., and I. Fatt. Conditions for countergradient diffusion of oxygen through a hemoglobin barrier. In: Chemical Engineering in Medicine and Biology, edited by D. Hershey. New York: Plenum, 1967, p. 107–115.
 115. LaGattuta, K. J., V. S. Sharma, D. F. Nicoli, and B. K. Kothari. Diffusion coefficients of hemoglobin by intensity fluctuation spectroscopy. Effects of varying pH and ionic strength. Biophys. J. 33: 63–79, 1981.
 116. Livingston, D. J., G. N. La Mar, and W. D. Brown. Myoglobin diffusion in bovine heart muscle. Science Wash. DC 220: 71–73, 1983.
 117. Longmuir, I. S., R. E. Forster, and C.‐Y. Woo. Diffusion of carbon dioxide through thin layers of solution. Nature Lond. 209: 393–394, 1966.
 118. Longmuir, I. S., D. C. Martin, H. J. Gold, and S. Sun. Nonclassical respiratory activity of tissue slices. Microvasc. Res. 3: 125–141, 1971.
 119. Longmuir, I. S., and M. G. P. McCabe. Evidence for an oxygen carrier in tissue. J. Polarogr. Soc. 10: 45–48, 1964.
 120. Longo, L. D. Placental diffusing capacity for carbon monoxide (letter to the editor). J. Appl. Physiol. 45: 155, 1978.
 121. Makino, N., H. Kanaide, R. Yoshimura, and M. Nakamura. Myoglobin oxygenation remains constant during the cardiac cycle. Am. J. Physiol. 245 (Heart Circ. Physiol. 14): H237–H243, 1983.
 122. Meldon, J. H. The theoretical effect of diffusion potential on carbon dioxide transport in protein solutions. Int. Biophys. Congr., 5th, Copenhagen, 1975, Abstract 413.
 123. Meldon, J. H. The effect of diffusion potentials on facilitated CO2 diffusion. In: Biophysics and Physiology of Carbon Dioxide, edited by C. Bauer, G. Gros, and H. Bartels. Berlin: Springer‐Verlag, 1980, p. 49–57. (Symp. Univ. Regensburg, April 17–20, 1979.)
 124. Meldon, J. H., J. De Koning, and P. Stroeve. Electrical potentials induced by CO2 gradients in protein solutions and their role in CO2 transport. Bioelectrochem. Bioenerg. 5: 77–87, 1978.
 125. Meldon, J. H., K. A. Smith, and C. K. Colton. The effect of weak acids upon the transport of carbon dioxide in alkaline solutions. Chem. Eng. Sci. 32: 939–950, 1977.
 126. Meldon, J. H., K. A. Smith, and C. K. Colton. An analysis of electrical effects induced by carbon dioxide transport in alkaline solutions. Recent Developments in Separation Science, edited by N. N. Li. Boca Raton, FL: CRC, 1979, vol. 5, p. 1–10.
 127. Meldon, J. H., P. Stroeve, and C. E. Gregoire. Facilitated transport of carbon dioxide: a review. Chem. Eng. Commun. 16: 263–300, 1982.
 128. Meyer, M., W. Lessner, P. Scheid, and J. Piiper. Pulmonary diffusing capacity for CO independent of alveolar CO concentration. J. Appl. Physiol. 51: 571–576, 1981.
 129. Millikan, G. A. Muscle hemoglobin. Physiol. Rev. 19: 503–523, 1939.
 130. Mitchell, P. J., and J. D. Murray. Facilitated diffusion: the problem of boundary conditions. Biophysik 9: 177–190, 1973.
 131. Mochizuki, M., and R. E. Forster. Diffusion of carbon monoxide through thin layers of hemoglobin solution. Science Wash. DC 138: 897–898, 1962.
 132. Moll, W. The diffusion coefficient of haemoglobin. Respir. Physiol. 1: 357–365, 1966.
 133. Moll, W. The diffusion coefficient of myoglobin in muscle homogenate. Pfluegers Arch. 299: 247–251, 1968.
 134. Moll, W. The influence of hemoglobin diffusion on oxygen uptake and release by red cells. Respir. Physiol. 6: 1–15, 1968.
 135. Moll, W. Measurements of facilitated diffusion of oxygen in red blood cells at 37°C. Pfluegers Arch. 305: 269–278, 1969.
 136. Murray, J. D. On the molecular mechanism of facilitated oxygen diffusion by haemoglobin and myoglobin. Proc. R. Soc. Lond. B Biol. Sci. 178: 95–110, 1971.
 137. Murray, J. D. On the role of myoglobin in muscle respiration. J. Theor. Biol. 47: 115–126, 1974.
 138. Murray, J. D. On the functional role of myoglobin in skeletal muscle. In: Myoglobin: Colloq. on Myoglobin, Brussels, May 22, 1976, p. 179–201.
 139. Murray, J. D., and J. Wyman. Facilitated diffusion. The case of carbon monoxide. J. Biol. Chem. 246: 5903–5906, 1971.
 140. Nedelman, J., and S. I. Rubinow. Facilitated diffusion of oxygen and carbon monoxide in the large affinity regime. J. Math. Biol. 12: 73–90, 1981.
 141. Noble, R. D. Shape factors in facilitated transport through membranes. Ind. Eng. Chem. Fundam. 22: 139–144, 1983.
 142. Noble, R. D. Two‐dimensional permeate transport with facilitated transport membranes. Sep. Sci. Technol. 19: 469–478, 1984.
 143. Noble, R. D. Kinetic efficiency factors for facilitated transport membranes. Sep. Sci. Technol. 20: 577–585, 1985.
 144. Olander, D. R. Simultaneous mass transfer and equilibrium chemical reaction. AIChE J. 6: 233–239, 1960.
 145. Otto, N. C., and J. A. Quinn. The facilitated transport of carbon dioxide through bicarbonate solutions. Chem. Eng. Sci. 26: 949–961, 1971.
 146. Phillies, G. D. J., G. B. Benedek, and N. A. Mazer. Diffusion in protein solutions at high concentrations: a study by quasielastic light scattering spectroscopy. J. Chem. Phys. 65: 1883–1892, 1976.
 147. Power, G. G., and W. C. Bradford. Measurement of pulmonary diffusing capacity during blood‐to‐gas exchange in humans. J. Appl. Physiol. 27: 61–66, 1969.
 148. Riveros‐Moreno, V., and J. B. Wittenberg. The self‐diffusion coefficients of myoglobin and hemoglobin in concentrated solutions. J. Biol. Chem. 247: 895–901, 1972.
 149. Roughton, F. J. W. Diffusion and chemical reaction velocity as joint factors in determining the rate of uptake of oxygen and carbon monoxide by the red blood corpuscle. Proc. R. Soc. Lond. B Biol. Sci. 111: 1–36, 1932.
 150. Rubin, D. Z., D. Fujino, C. Mittman, and S. M. Lewis. Competitive inhibition of carbon monoxide transport: evidence against a carrier. J. Appl. Physiol. 50: 1061–1064, 1981.
 151. Rubinow, S. I., and M. Dembo. The facilitated diffusion of oxygen by hemoglobin and myoglobin. Biophys. J. 18: 29–42, 1977.
 152. Sanders, A. H., D. L. Purich, and D. S. Cannell. Oxygen‐ation of hemoglobin. Correspondence of crystal and solution properties using diffusion coefficient measurements. J. Mol. Biol. 147: 583–595, 1981.
 153. Scheid, P., T. Kawashiro, and J. Piiper. Evidence for facilitated transport of CO2 in muscle tissue. In: Biophysics and Physiology of Carbon Dioxide, edited by C. Bauer, G. Gros, and H. Bartels. Berlin: Springer‐Verlag, 1980, p. 58–63. (Symp. Univ. Regensburg, April 17–20, 1979.)
 154. Scholander, P. F. Oxygen transport through hemoglobin solutions. Science Wash. DC 131: 585–590, 1960.
 155. Schultz, J. S. Facilitation of CO2 through layers with a spatial distribution of carbonic anhydrase. In: Biophysics and Physiology of Carbon Dioxide, edited by C. Bauer, G. Gros, and H. Bartels. Berlin: Springer‐Verlag, 1980, p. 15–22. (Symp. Univ. Regensburg, April 17–20, 1979.)
 156. Schultz, J. S., J. D. Goddard, and S. R. Suchdeo. Facilitated transport via carrier‐mediated diffusion in membranes. I. Mechanistic aspects, experimental systems and characteristic regimes. AIChE J. 20: 417–445, 1974.
 157. Schwarzmann, V., and W. A. Grunewald. Myoglobin‐O2‐saturation profiles in muscle sections of chicken gizzard and the facilitated O2 transport by Mb. Adv. Exp. Med. Biol. 94: 301–310, 1978.
 158. Sheth, B. V., and J. D. Hellums. Transient oxygen transport in hemoglobin layers under conditions of the microcirculation. Ann. Biomed. Eng. 8: 183–196, 1980.
 159. Smith, D. R., and J. A. Quinn. The prediction of facilitation factors for reaction augmented membrane transport. AIChE J. 25: 197–200, 1979.
 160. Smith, K. A., J. H. Meldon, and C. K. Colton. An analysis of carrier‐facilitated transport. AIChE J. 19: 102–111, 1973.
 161. Spaan, J. A. E. Transfer of oxygen into haemoglobin solution. Pfluegers Arch. 342: 289–306, 1973.
 162. Spaan, J. A. E., F. Kreuzer, and L. Hoofd. A theoretical analysis of nonsteady‐state oxygen transfer in layers of hemoglobin solution. Pfluegers Arch. 384: 231–239, 1980.
 163. Spaan, J. A. E., F. Kreuzer, and F. K. van Wely. Diffusion coefficients of oxygen and hemoglobin as obtained simultaneously from photometric determination of the oxygenation of layers of hemoglobin solutions. Pfluegers Arch. 384: 241–251, 1980.
 164. Spaeth, E. E., and S. K. Friedlander. The diffusion of oxygen, carbon dioxide, and inert gas in flowing blood. Biophys. J. 7: 827–851, 1967.
 165. Spavins, J. C. Interplay of Diffusion, Chemical Reactions and Electrical Potentials in Thin Liquid Films. Buffalo: State Univ. of New York, 1980. Master's thesis.
 166. Stein, T. R., J. C. Martin, and K. H. Keller. Steady‐state oxygen transport through red blood cell suspensions. J. Appl. Physiol. 31: 397–402, 1971.
 167. Stevens, E. D. The effect of temperature on facilitated oxygen diffusion and its relation to warm tuna muscle. Can. J. Zool. 60: 1148–1152, 1982.
 168. Stevens, E. D., and F. G. Carey. One why of the warmth of warm‐bodied fish. Am. J. Physiol. 240 (Regulatory Integrative Comp. Physiol. 9): R151–R155, 1981.
 169. Stroeve, P. On the diffusion of gases in protein solutions. Ind. Eng. Chem. Fundam. 14: 140–141, 1975.
 170. Stroeve, P. Myoglobin‐facilitated oxygen transport in heterogeneous red muscle tissue. Ann. Biomed. Eng. 10: 49–70, 1982.
 171. Stroeve, P. Diffusion with chemical reaction in two‐phase heterogeneous media. In: Advances in Transport Processes, edited by E. F. Mujumbar and R. A. Mashelkar. New Delhi: Wiley, 1984, vol. 3, p. 361–386.
 172. Stroeve, P., C. K. Colton, and K. A. Smith. Steady state diffusion of oxygen in red blood cell and model suspensions. AIChE J. 22: 1133–1142, 1976.
 173. Stroeve, P., and K. Eagle. An analysis of diffusion in a medium containing dispersed reactive cylinders. Chem. Eng. Commun. 3: 189–198, 1979.
 174. Stroeve, P., and K. Eagle. Myoglobin‐facilitated oxygen transport in heterogeneous red muscle tissue. In: Advances in Bioengineering, edited by V. C. Mow. New York: Am. Soc. Mech. Eng., 1980, p. 341–344.
 175. Stroeve, P., K. A. Smith, and C. K. Colton. An analysis of carrier facilitated transport in heterogeneous media. AIChE J. 22: 1125–1132, 1976.
 176. Stroeve, P., P. P. Varanasi, and L. J. C. Hoofd. Facilitated transport in spherical shells: application of the combined Damköhler number technique. J. Membr. Sci. 19: 155–171, 1984.
 177. Stroeve, P., and E. Ziegler. The transport of carbon dioxide in high molecular weight buffer solutions. Chem. Eng. Commun. 6: 81–103, 1980.
 178. Suchdeo, S. R., J. D. Goddard, and J. S. Schultz. An analysis of the competitive diffusion of O2 and CO through hemoglobin solutions. Adv. Exp. Med. Biol. 37B: 951–961, 1973.
 179. Suchdeo, S. R., and J. S. Schultz. Mass transfer of CO2 across membranes: facilitation in the presence of bicarbonate ion and the enzyme carbonic anhydrase. Biochim. Biophys. Acta 352: 412–440, 1974.
 180. Suchdeo, S. R., and J. S. Schultz. The permeability of gases through reacting solutions: the carbon dioxide‐bicarbonate membrane system. Chem. Eng. Sci. 29: 13–23, 1974.
 181. Tamura, M., N. Oshino, B. Chance, and I. A. Silver. Optical measurements of intracellular oxygen concentration of rat heart in vitro. Arch. Biochem. Biophys. 191: 8–22, 1978.
 182. Taylor, B. A., and J. D. Murray. Effect of the rate of oxygen consumption on muscle respiration. J. Math. Biol. 4: 1–20, 1977.
 183. Ulanowicz, R. E., and G. C. Frazier, Jr. The transport of oxygen and carbon dioxide in hemoglobin systems. Math. Biosci. 7: 111–129, 1970.
 184. Van Ouwerkerk, H. J. Facilitated diffusion in a tissue cylinder with an anoxic region. Pfluegers Arch. 372: 221–230, 1977.
 185. Veldkamp, W. B., and J. R. Votano. Effects of intermolecular interaction on protein diffusion in solution. J. Phys. Chem. 80: 2794–2801, 1976.
 186. Veldkamp, W. B., and J. R. Votano. Temperature dependence of macromolecular interactions in dilute and concentrated hemoglobin solutions. Biopolymers 19: 111–124, 1980.
 187. Venkataraman, K., T. Wang, and P. Stroeve. Oxygen diffusion into heterogeneous tissue with combined oxygen consumption kinetics. Ann. Biomed. Eng. 8: 17–27, 1970.
 188. Warburg, O. Versuche an überlebendem Carcinomgewebe (Methoden). Biochem. Z. 142: 317–333, 1923.
 189. Ward, W. J., III. Analytical and experimental studies of facilitated transport. AIChE J. 16: 405–410, 1970.
 190. Ward, W. J., III, and W. L. Robb. Carbon dioxide‐oxygen separation: facilitated transport of carbon dioxide across a liquid film. Science Wash. DC 156: 1481–1484, 1967.
 191. Way, J. D., R. D. Noble, T. M. Flynn, and E. D. Sloan. Liquid membrane transport: a survey. J. Membr. Sci. 12: 239–259, 1982.
 192. Weigelt, C. Mikrokryophotometrische Messungen zur Untersuchung des erleichterten Sauerstofftransports in Gegenwart von Hämoglobin. Bochum, FGR: Bochum Univ., 1975. Dissertation.
 193. Wilson, W. W., M. R. Luzzana, J. T. Penniston, and C. S. Johnson, Jr. Pregelation aggregation of sickle cell hemoglobin. Proc. Natl. Acad. Sci. USA 71: 1260–1263, 1974.
 194. Wittenberg, B. A., and M. J. Monahan. Intracellular oxygen gradients in isolated cardiac cells during controlled steady state hypoxia (Abstract). J. Mol. Cell. Cardiol. 14, Suppl. 1: 69, 1982.
 195. Wittenberg, B. A., and T. F. Robinson. Oxygen requirements, morphology, cell coat and membrane permeability of calcium‐tolerant myocytes from hearts of adult rats. Cell Tissue Res. 216: 231–251, 1981.
 196. Wittenberg, B. A., J. B. Wittenberg, and P. R. B. Caldwell. Role of myoglobin in the oxygen supply to red skeletal muscle. J. Biol. Chem. 250: 9038–9043, 1975.
 197. Wittenberg, J. B. Oxygen transport—a new function proposed for myoglobin. Biol. Bull. Woods Hole 117: 402–403, 1959.
 198. Wittenberg, J. B. The molecular mechanism of hemoglobin‐facilitated oxygen diffusion. J. Biol. Chem. 241: 104–114, 1966.
 199. Wittenberg, J. B. Myoglobin‐facilitated oxygen diffusion: role of myoglobin in oxygen entry into muscle. Physiol. Rev. 50: 559–636, 1970.
 200. Wittenberg, J. B., and B. A. Wittenberg. Facilitated oxygen diffusion by oxygen carriers. In: Oxygen and Living Processes: An Interdisciplinary Approach, edited by D. L. Gilbert. New York: Springer‐Verlag, 1981, p. 177–199.
 201. Wyman, J. Facilitated diffusion and the possible role of myoglobin as a transport mechanism. J. Biol. Chem. 241: 115–121, 1966.
 202. Young, M. E., P. A. Carroad, and R. L. Bell. Estimation of diffusion coefficients of proteins. Biotechnol. Bioeng. 22: 947–955, 1980.
 203. Yung, D., and R. F. Probstein. Similarity considerations in facilitated transport. J. Phys. Chem. 77: 2201–2205, 1973.
 204. Zander, R., and H. Schmid‐Schönbein. Influence of intra‐cellular convection on the oxygen release by human erythrocytes. Pfluegers Arch. 335: 58–73, 1972.
 205. Zborowska‐Sluis, D. T., A. L'Abbate, and G. A. Klassen. Evidence of carbonic anhydrase activity in skeletal muscle: a role for facilitative carbon dioxide transport. Respir. Physiol. 21: 341–350, 1974.

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Ferdinand Kreuzer, Louis Hoofd. Facilitated Diffusion of Oxygen and Carbon Dioxide. Compr Physiol 2011, Supplement 13: Handbook of Physiology, The Respiratory System, Gas Exchange: 89-111. First published in print 1987. doi: 10.1002/cphy.cp030406