摘要
The ionizing groups at the active site of alkaline phosphatase （ALP, EC 3.1.3.1） from Ostrea cucullate were studied using kinetic methods. The ionization constant, pKe, of the ionizing groups at the active site of the enzyme was found to be 10.11 at 37.0℃ and the organic solvent, dioxin, had no effect on the pKe. The standard dissociation enthalpy （△Hρ） was determined to be 10.57 kcal/mol （1 ca1=4.18 J）. The results show that the dissociation group of the enzyme active center is the ε-NH3^＋ of lysine. Chemical modification of the enzyme by acetic anhydride and succinic anhydride demonstrates that the amino group is one of the enzyme＇s functional groups.
The ionizing groups at the active site of alkaline phosphatase （ALP, EC 3.1.3.1） from Ostrea cucullate were studied using kinetic methods. The ionization constant, pKe, of the ionizing groups at the active site of the enzyme was found to be 10.11 at 37.0℃ and the organic solvent, dioxin, had no effect on the pKe. The standard dissociation enthalpy （△Hρ） was determined to be 10.57 kcal/mol （1 ca1=4.18 J）. The results show that the dissociation group of the enzyme active center is the ε-NH3^＋ of lysine. Chemical modification of the enzyme by acetic anhydride and succinic anhydride demonstrates that the amino group is one of the enzyme＇s functional groups.
基金
Supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, the Ministry of Education, China
