Hemoglobin Creteil: oxygen transport by erythrocytes. In-vitro and in-vivo studies in a high oxygen-affinity mutant hemoglobin.

Hemoglobin Hb) Creteil alpha2beta(2)89 (F5) Ser leads to Asn is a high oxygen-affinity variant that has a low cooperativity, a decreased Bohr effect, and does not interact with diphosphoglycerate (DPG) (1). This hemoglobin variant was silent by routine electrophoresis. Careful analyses of the oxygen dissociation curves of erythrocytes, determined at varying pH and Pco2 in fresh and DPG-depleted cells, gave extensive information on the abnormal function of the mutant hemoglobin. 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 one half of the total hemoglobin present actually participated in oxygen transport. Polycythemia should therefore be maintained within clinically tolerable limits because it helps to keep arterial Po2 and Pvo2 close to their normal values and thus protects the individual from a permanent increase in blood flow.