Glyceraldehyde metabolism in human erythrocytes in comparison with that of glucose and dihydroxyacetone

Metabolism of D ‐glyceraldehyde in human erythrocytes in comparison with that of glucose and dihydroxyacetone was studied. Both trioses were metabolized to produce L ‐lactate at rates comparable to that of L ‐lactate formation from glucose. Almost complete inactivation of glyceraldehyde‐3‐phosphate dehydrogenase by treatment of cells with iodoacetate resulted in a 95% decrease in L ‐lactate formation from the ketotriose as well as from glucose, whereas L ‐lactate formation from the aldotriose was only partially reduced (60%). D ‐Lactate was produced faster from either the aldotriose or the ketotriose than from glucose, but the ability of the two trioses to produce D ‐lactate was far lower than that to produce L ‐lactate. Almost complete inhibition of aldehyde dehydrogenase by disulfiram and of both aldose reductase and aldehyde reductase II by sorbinil, had no effect on L ‐lactate formation from D ‐glyceraldehyde. The present study suggests that D ‐glyceraldehyde is metabolized via two or more pathways including the glycolytic pathway after its phosphorylation by triokinase, and that neither oxidation to D ‐glyceric acid nor reduction to glycerol is a prerequisite for D ‐glyceraldehyde metabolism. Copyright © 2002 John Wiley & Sons, Ltd.