Isomerization of L-glyceraldehyde to dihydroxyacetone during glyceride synthesis by rat liver microsomes.

Abstract

AbstractL‐glyceraldehyde is converted to phosphatidic acid by the action of rat liver microsomal enzymes and glycerol kinase in the presence of fatty acid, ATP, CoASH and NADH. L‐glycerol 3‐phosphate is not an intermediate in this synthesis since microsomes in the presence of NADH neither reduce L‐glyceraldehyde nor, in the additional presence of glycerol kinase and ATP, convert it to L‐glycerol 3‐phosphate. However dihydroxyacetone is produced when L‐glyceraldehyde is incubated with microsomes. This was shown enzymatically by the subsequent conversion to dihydroxyacetone phosphate which was confirmed by the oxidation of NADH in the presence of glycerol 3‐phosphate dehydrogenase. Isomerization of L‐glyceraldehyde and the synthesis of dihydroxyacetone phosphate may be one of several possible mechanisms in the conversion of the triose to either glucose or glycerideglycerol which has been reported to occur in tissue.