The kinetics of human haemoglobin in solution and in the red cell at 37° c

Abstract

One of the original objects, which Hartridge & Roughton (1923) had in mind in developing their method of measuring the velocity of rapid chemical reactions, was to estimate the extents to which the rates of the reactions of haemoglobin, in the intact red cell, with oxygen and/or carbon monoxide limit the rate of uptake of these gases in the human lung. For these purposes, measurements are necessary of the rates of these reactions in human blood solutions and suspensions at physiological pH and temperature. Such determinations are so far almost wholly lacking, the only exceptions being the data obtained by Roughton (1945 a) on the rate at which carbon monoxide displaces oxygen from combination with oxygenated human haemoglobin, in solution and in red cell suspensions. These data were used by him (1945b) in estimating, by a theoretical method, the average time spent by the blood in traversing the capillaries of the lung. It is the aim of the present paper to fill some of the many existing gaps in knowledge as to the kinetics, in vitro, of human haemoglobin in solution and in the red cell, not only for the intrinsic interest of such studies, but also to provide the necessary basis for the solution of further problems of physiological interest in human subjects in vivo.The present paper contains measurements of:(i) The rate of combination of (a) oxygen, (b) carbon monoxide, at 370 C, with human haemoglobin, both in dilute solution and in suspensions of intact red cells.(ii) The effect of temperature on (a) the rate of combination of carbon monoxide with dilute human haemoglobin solutions, (b) the rate of dissociaton of the first oxygen molecule from fully saturated human oxyhaemoglobin solutions.

The effect of the red cell membrane and a diffusion boundary layer on the rate of oxygen uptake by human erythrocytes

“…Students of the kinetics of chemical reactions in rapid-reaction apparatuses have traditionally assumed that the mixing of reactant solutions in the mixing chamber is complete and remains free of molecular-diffusion-limited domains over the time course of the measurements (Hartridge & Roughton, 1923, 1927Gibson, Kreuzer, Meda & Roughton, 1955;Roughton, 1959). This assumption was tested by the application of careful control measurements of the rates of rapid inorganic reactions and the evidence of being able to measure the rates of these rapid reactions is used as justification for the adequacy of mixing of reactant solutions containing 81 82 V. H. HUXLEY AND H. KUTCHAI macromolecular or particulate species (Hartridge & Roughton, 1927;Roughton, 1932;Nicholson & Roughton, 1951;Carlsen & Comroe, 1958;Holland & Forster, 1966).…”

Synergism in the kinetic reactions of O2 and CO2 with human red blood cells*

“…In our study, since the initial saturation is high (97-98 %) we are dealing mostly with the fourth pair of the velocity constants, namely k4 and k1 , and some data as to their magnitude and pH sensitivity are available. Gibson & Roughton (1954), and Gibson, Kreuzer, Meda & Roughton (1955) have calculated k4 from data on the rate of replacement of 02 by CO in fully-saturated O2Hb solutions. If all their kinetic assumptions are correct then the extrapolated value of k1 for human haemoglobin at 370 C is about 200 sec-1 and it is insensitive to pH over the range 7-1-9 1.…”

A quantitative framework for the design of acellular hemoglobins as blood substitutes: Implications of dynamic flow conditions

“…To reflect differences in k′ and k due to equilibrium binding effects, Moll developed a technique that holds the association coefficient constant and varies the dissociation coefficient in the Hill equation as a function of saturation, Y (8) [28]. (8) The value for k′ is given by Gibson et al as 3.5 × 10 6 M −1 s −1 for Hb at 37°C [29]. The use of constant association and variable disassociation coefficients to define activity for different Hbs is consistent with kinetic measurements for native and chemically-modified Hb [30,31].…”