The Reduction of Glyceraldehyde by Human Erythrocytes L-HEXONATE DEHYDROGENASE ACTIVITY

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Abstract
Incubation of red cell suspensions with D-glyceraldehyde resulted in disappearance of glyceraldehyde and appearance of glycerol. Concomitantly, there was an increase of CO2 formation from glucose. This indicated that the reduction of glyceraldehyde to glycerol occurred through a NADPH-linked system. Studies in hemolysates revealed the presence of an enzyme with the capacity to catalyze the reduction of glyceraldehyde to glycerol by NADPH. This enzyme was partially purified by DEAE chromatography. The elution pattern of the enzyme and its kinetic characteristics indicated that the enzyme was L-hexonate dehydrogenase (L-gulonate: NADP oxidoreductase, EC 1.1.1.19), not aldose reductase (Alditol: NADP oxidoreductase, EC 1.1.1.21), which had previously been thought present in erythrocytes. The reduction of glyceraldehyde to glycerol is one of a number of pathways for the metabolism of glyceraldehyde that have been found in red cells and/or other mammalian tissues.