Members of this protein family are the eukaryotic enzyme, glycerol-3-phosphate dehydrogenase (NAD(+)) (EC 1.1.1.8). Enzymatic activity for 1.1.1.8 is defined as sn-glycerol 3-phosphate + NAD(+) = glycerone phosphate + NADH. Note the very similar reactions of enzymes defined as EC 1.1.1.94 and 1.1.99.5, assigned to families of proteins in the bacteria.