Erythrocyte Glycolytic Intermediates and Cofactors Correlated with the Haemoglobin Concentration in Human Neonates and Adults

Abstract

Human erythrocytes are highly specialized cells containing haemoglobin for the transport of oxygen. It seems reasonable to assume that their simplified metabolic systems, the glycolytic pathway and the pentose phosphate shunt, is essential for the maintenance of this oxygen carrying function. It has previously been reported that reduced glutathione (GSH) influences the affinity of haemoglobin to oxygen in intact erythrocytes (cf. Horejsi 1967) and it has recently been found, that several organic phosphocompounds, some of which are normally present in human erythrocytes, bind to haemoglobin in vitro (Chanutin & Curnish 1964, Benesch & Benesch 1968, Garby & de Verdier 1968). Most of the compounds investigated showed a higher affinity for deoxygenated than for oxygenated haemoglobin. The binding is correlated with an decreased affinity of the haemoglobin molecule for oxygen (Chanutin & Curnish 1967, Benesch & Benesch 1967). If these findings are relevant also for the conditions in vivo, then there should be a correlation between the average amount of deoxygenated haemoglobin and the binding of organic phosphocompounds, i.e. the molar ratio of phosphocompound to haemoglobin should increase with increasing average deoxygenation of the circulating haemoglobin. Several pieces of evidence have also been obtained, that support this concept. An increased content of phosphocompounds, mainly 2,3-diphosphoglycerate (DPG) and ATP, has been found in erythrocytes from subjects with a decrease of the oxygen saturation of the blood (Lenfant et al. 1969) or where it seems likely to assume that the time average concentration of deoxygenated haemoglobin is increased (Eaton & Brewer 1968, Hjelm 1968, 1969, Fortier & Valeri 1969).