摘要
采用生化手段，从长吻（ＬｅｉｏｃａｓｓｉｓｌｏｎｇｉｒｏｓｔｒｉｓＧｕｎｔｈｅｒ）肝中提取出碱性磷酸酶（ＡＫＰ）。提纯倍数为６２．０８倍，比活为６６．４３单位／ｍｇ蛋白，提取酶液经ＰＡＧＥ和ＳＤＳ－ＰＡＧＥ只呈现一条区带。该酶的最适ｐＨ为１０．０５，７．０＞ｐＨ＞１１．０时不稳定；最适温度为４０℃，；对热不很稳定；以磷酸苯二钠为底物其Ｋｍ值为１．８２×１０￣（－３）ｍｏｌ／Ｌ。Ｍｇ￣（２＋）为该酶的激活剂，Ｌ－Ｃｙｓ、ＫＨ＿２ＰＯ＿４、ＤＦＰ、ＭＥ、ＥＤＴＡ－Ｎａ＿２为抑制剂。选用ＫＨ＿２ＰＯ＿４，和ＤＦＰ作抑制类型的判断，结果表明，ＫＨ＿２ＰＯ＿４，属竞争性抑制剂，其抑制常数为２．４１ｍｍｏｌ／Ｌ，ＤＦＰ为非竞争性抑制剂，抑制常数为１．０１ｍｍｏｌ／Ｌ。
Alkaline phosphatase(AKP)was purified from the liver of Leiocassis longiros-tris by a biochemical method.The purification multiple was 6 2.0 8 and the specificactivity was 66.43 unit/mg protein,In PAGE and SDS-PAGE,the liver of Leiocas-sis longirostris AKP formed a single band.The optimum pH for the enzyme waspH10.05;when 7.0>pH>11,it was uhstable. The optimum temperature was abo-ut 40℃,it was unstable against heat.The Km value was 1.82×10￣(-3)mol/L withdisodium phenyl phosphate as its substrate. The activator of the enzyme was Mg￣(2+),while inhibitors were KH_2PO_4,L-Cys,ME,DFP,and EDTA-Na_2,KH_2PO_4 andDFP were selected for determining the types of inhibhion and the results showedthat KH_2PO_4 was a competitive inhibitor with the inhibition constant being 2.41mmol/L,and that DFP was a noncompetitive inhibitor with the inhibition constantbeing 1.01m mol/L.
出处
《水生生物学报》
CAS
CSCD
北大核心
1995年第4期338-343,共6页
Acta Hydrobiologica Sinica
关键词
长吻WEI
碱性磷酸酶
动力学
鱼纲
Leiocassis longirostris Gunther,Liver,Alkaline phosphatase,Kinetics
