三角帆蚌碱性磷酸酶的初步研究

PURIFICATION AND PROPERTIES OF ALKALINE PHOSPHATASE FROM THE PALLIUM OF HYRIOPSIS CUMINGII (LEA)

从三角帆蚌外套膜中,部分提纯了一种碱性磷酸酶(AKP),并对AKP的某些性质进行了初步研究。该酶作用于底物磷酸苯二钠,测定其最适pH值为10.1,最适温度为40℃,Km值为1.82×10^(-3)mol/L。分别测定了某些化学试剂对该酶的作用:Mg^(2+),Ca^(2+)离子对AKP有不同程度的激活,尤以Mg^(2+)的作用明显;KH_2PO_4,L-Phe,L-Cys,ME(巯基乙醇),DFP(二异丙基氟磷酸)和EDTA-Na均对AKP有不同程度的抑制作用,其中L-Cys和ME抑制作用最为强烈。KH_2PO_4对AKP的作用属于竞争性抑制,而DFP属于非竞争性抑制。

The alkaline phosphatase was partially purified from the pallium of Hyriopsis cumingii by n-butanol extraction, ammonium sulfate fractionation and gel filtration with Sephadex G-100.The pH optimum of the AKP for the hydrolysis of disodium phenyl phosphate is 10.1, and the optimum temperature is 40℃. The Michaelis Menten constant Km is 1.82×10-3mol.The AKP is activated by Mg2+ and Ca2+ ion. On the other hand, it is inhibited by the KH2PO4, L-Phe, L-Cys, ME, DFP and EDTA-Na, the inhibition of L-Cys and ME is the strongest among them. To the AKP, the KH2PO4 is a competitive inhibitor, and the DFP is a noncompetitive inhibitor.