GPD1 enzyme catalyzes the reduction of dihydroxyacetone phosphate to sn-glycerol 3-phosphate.(sn-glycerol 3-phosphate + NAD+ = glycerone phosphate + NADH) previous names for glycerol-3-phosphate dehydrogenase include alpha glycerol-3-phosphate dehydrogenase and glycerolphosphate dehydrogenase. However, GPD1 differs from glyceraldehyde 3-phosphate dehydrogenase(GAPDH) whose substrate is an aldehyde not an alcohol.