文章基本信息

标题：Zinc-Ion-Dependent Acid Phosphatase Exhibits Magnesium-Ion-Dependent myo-Inositol-1-phosphatase Activity
本地全文：下载
作者：Sadaki FUJIMOTO ; Isako OKANO ; Yutaka TANAKA 等
期刊名称：Biological and Pharmaceutical Bulletin
印刷版ISSN：0918-6158
电子版ISSN：1347-5215
出版年度：1996
卷号：19
期号：6
页码：882-885
DOI：10.1248/bpb.19.882
出版社：The Pharmaceutical Society of Japan
摘要：We have purified bovine brain Zn²⁺-dependent acid phosphatase (Zn²⁺-APase), which requires Zn²⁺ ions to hydrolyze the substrate p-nitrophenyl phosphate (pNPP) in an acidic environment. The substrate specificity and metal requirement of Zn²⁺-APase at a physiological pH was also studied. The enzyme exhibited hydrolytic activity on myo-inositol-1-and-2-monophosphates, 2'-adenosine monophosphate, 2'-guanosine monophosphate, and the α- and β-glycerophosphates, glucose-1-phosphate, and fructose-6-phosphate in 50 mM Tris-HCl buffer (pH 7.4) in the presence of Mg²⁺ ions, but not on pNPP and phosphotyrosine. Zn²⁺, Mn²⁺ and Co²⁺ ions were less effective for activation. Among the above substrates, myo-inositol-1-phosphate was the most susceptible to hydrolysis by the enzyme in the presence of Mg²⁺ ions. The enzyme exhibited an optimum pH at around 8 for myo-inositol-1-phosphate in the presence of 3 mM Mg²⁺ ions. The Mg²⁺-dependent myo-inositol-1-phosphatase activity of the enzyme was significantly inhibited by Li⁺ ions. The Zn²⁺-dependent p-nitrophenyl phosphatase activity and Mg²⁺-dependent myo-inositol-1-phosphatase activity of the purified enzyme fraction exhibited similar behavior on Sephadex G-100 and Mono Q colomns. These findings suggest that Zn²⁺-APase also exhibits Mg²⁺-dependent myo-inositol-1-phosphatase activity under physiological conditions.
关键词：acid phosphatase;zinc dependent;myo-inositol-1-phosphatase;magnesium dependent;bovine brain