forms of glycerol 3-phosphate dehydrogenase. [ 7 ] GPDH-C and GPDH-M use NADH and quinol (QH) as an electron donors respectively. GPDH-M in addition uses FAD as a co-factor. [ edit ] Variants There are two forms of GPDH: Enzyme Protein Gene EC number Name Donor / Acceptor Name Subcellular location