Hemoglobin Creteil: Oxygen Transport by Erythrocytes

Abstract

Hemoglobin (Hb) Creteil .alpha.2.beta.289 (F5) Ser .fwdarw. Asn is a high oxygen-affinity variant that has a low cooperativity, a decreased Bohr effect and does not interact with diphosphoglycerate (DPG). This Hb variant was silent by routine electrophoresis. Careful analyses of the oxygen dissociation curves of [human] erythrocytes, determined at varying pH and PCO2 [CO2 pressure] in fresh and DPG-depleted cells, gave extensive information on the abnormal function of the mutant Hb. From the O2 dissociation curves of the erythrocytes of the heterozygous subject it appeared that Hb Creteil is inappropriate for O2 transport to the tissues because it remained completely saturated with O2 at normal physiologic levels of PO2. In-vivo measurements showed that only 1/2 of the total Hb present actually participated in oxygen transport. Polycythemia should be maintained within clinically tolerable limits because it helps to keep arterial PO2 and P.hivin.VO+2 close to their normal values and protects the individual from a permenent increase in blood flow.