Kinetics of combination of O 2 and CO with human hemoglobin F in cells and in solution

Abstract

Kinetic constants for the combination of oxygen and carbon monoxide with reduced human fetal hemoglobin in cells and solution were measured using a double beam stopped-flow apparatus. At 37 °C the mean velocity constant for the uptake of oxygen by reduced fetal red cells was 83 mM -1. sec -1 and for the uptake of CO was 68 mM -1.sec -1, these being little different from values previously found for adult cells. For combination of CO with reduced fetal hemoglobin solution the velocity constant was 370 mM -1.sec -1 at 37 °C and the energy of activation was 9.2 kcal/mole. The results indicate that the chemical differences between human fetal and adult hemoglobin do not affect the rate of combination with carbon monoxide, and that the differences between fetal and adult red cells confer no advantage with respect to velocity of gas uptake. Carbon monoxide Reaction kinetics Fetal blood Red blood cells Hemoglobin Red cell membrane Oxygen