Product Description: α-Glycerophosphate Dehydrogenase-Triosephosphate (GDH-TIM) is an enzyme mixture composed of glycerol phosphate dehydrogenase (GDH) and triphosphate isomerase (TIM). α-Glycerophosphate Dehydrogenase-Triosephosphate can be used to determine the activity of transketolase (TK) in hemolytic substances of red blood cells to evaluate vitamin B deficiency[1][2].