【摘要】 <正> 緒言普通的磷酸酯酶有兩種,一種是在pH9左右活動的所謂“鹼活性”磷酸酯酶,在動物界分佈甚廣,研究得特別多;另一種是在pH5.5左近活動的“酸活性”磷酸酯酶,廣泛存在在高等植物及細菌體內,動物體的有些器官像肝、腎、腦及前列腺等含量較多,一般研究得較少,因此關於這類酶的知識比較貧乏。 綠荳是普通的食用種子,它的芽也是常用的食品,含磷酸酯酶頗為豐富,作更多还原

【Abstract】 Mung bean sprouts contained a phosphatase with a pH optimum of 5.6 in the crude state and one of 5.8 as the partially purified enzyme. The effect of substrate concentration, enzyme concentration and time of action on the activity of the enzyme have been studied. The Michaelis constant was 1.00×10^-3. Of the cations studied （Table 1）, copper and zinc have been found to be strong inhibitors of the enzyme. Ferric and ferrous iron, manganese, chromium and berrylium also inhibited to a large exten. Cobalt, nickel and cadmium showed only slight inhibition, while calcium and barium had no effect. Magnesium showed a slight activating effect only on the partially purified enzyme. Besides inhibiting the enzyme, zinc was also found to shift the optimum pH towards the acid side （Fig. 1）. Copper and chromium behaved similarly. Inhibition by zinc was demonstrated to be irreversible. With the help of kinetic studies, the nature of this inhibition was shown to be non-competitive （Table 3, Fig. 4）. Of the anions studied （Table 4）, vanadate, molybdate and tungstate were all strong inhibitors. Selenite and fluoride were next in potency. Borate and cyanide showed only slight effect. Iodoacetate, hydroxylamine hydrochloride, hydrazine hydrate and alloxan were without effect. Formaldelyde, acetaldehyde and acetone showed appreciable inhibition only at very high concentrations （0.1 to 1 M）. Below, 0.01 M they were entirely without effeot. The significance of these findings was discussed.更多还原