GAPC activity was measured by following the reduction of NAD+. The medium contained 50 mM triethanolamine-HCl, pH 8.5, 4 mM NAD+,10 mM Na3AsO4, 1.2 mMol D -Ga3P, and 3 mM dithiothreitol. Reactions were initiated by the addition o f Ga3P, and the rate of increase in absorbance w as linear for at least 3 to 5 min. Activity increased linearly with increasing enzyme concentration. One unit (U) is defined as the amount of enzyme that catalyzes the formation or consumption of 1 mMol min2 1 NADP H or NADH under e ach specified assay condition.