Oxygen equilibrium curves of fresh, normal human blood have been measured by new methods which allow the control of pH, p(CO 2) and 2,3 diphosphoglycerate and which yield higher accuracy at the extremes of saturation than was possible previously. The curve determined by these techniques lies slightly to the right of the standard curve of Roughton et al. The greatest difference is at low oxygen saturation, probably owing to the fact that the latter data were obtained under conditions which would lead to depletion of cellular 2,3 diphosphoglycerate. The range of p 50 (oxygen pressure at half saturation) values for four normal subjects was 28.3 mm Hg to 29.0 mm Hg. Adair's stepwise oxygenation scheme has been used to analyse the curves with the result that α 1 = 0.1514 x 10 -1 (± 10%) mm -1; α 2 = 0.9723 x 10 -3 (± 8%) mm -2; α 3 = 0.1703 x 10 -3 (± 50%) mm -3; α 4 = 0.1671 x 10 -5 (± 2%) mm -4 for the best of four data sets. Because these constants are very sensitive to changes in the shape of the oxygenation curve, this analysis is much more useful than p 50 measurements in the investigation of the various allosteric effects of the function of hemoglobin within the red cell.
|Number of pages||7|
|Journal||Journal of Biological Chemistry|
|Publication status||Published - 1977|
ASJC Scopus subject areas