Studies on human placental alkaline phosphatase

摘要: Abstract Human placental alkaline phosphatase is a non-specific capable of hydrolyzing compounds containing phosphomonoesters and pyrophosphates catalyzing both phosphorylation transphosphorylation reactions. The heat activation for hydrolysis 5′-AMP was calculated to be 10,375 cal/mole. A turnover number 40,500 moles/mole enzyme/min with the substrate p-nitrophenyl phosphate reported. enzyme competitively inhibited by inorganic phosphate, arsenate trimetaphosphate. Inactive apoenzyme, prepared dialysis against EDTA at pH 5.0, optimally reactivated Zn++ or Co++. Zn++-reactivated stable, whereas Co++-apoenzyme not. It concluded that Zn++-metalloenzyme.