水稻叶片酸性磷酸酯酶活性及其部分特性

ACID PHOSPHATASE ACTIVITY AND PARTIAL PROPERTIES IN RICE LEAVES

摘要:

从水稻叶片部分纯化了水解磷酸烯醇式丙酮酸的磷酸酯酶，其Ｋｍ（ＰＥＰ）为０．１ｍｍｏｌ／Ｌ，最适ＰＨ５．３．在偏酸性ＰＨ条件下（ＰＨ４．０～７．２）稳定，对热亦较稳定．酶活性受Ｐｉ强烈抑制．它对其底物要求不专一，能水解多种含磷酯键的化合物．表明它是一种非专一性的酸性磷酸酯酶。各种含磷酯键的代谢物对酶活性起竞争性抑制作用，且表现出叠加性．Ｃｕ（２＋）、Ｚｎ（２＋）和Ｆｅ（２＋）抑制酶活性，Ｍｇ（２＋）、Ｍｎ（２＋）、Ｃａ（２＋）、Ｃｏ（２＋）和ＥＤＴＡ无影响．

Abstract:

A phosphatase was partially purified from rice leaves by the steps of acidification (to pH 4. 5), ammonium sulfate precipitation, Sephadex G-50 chromatography and DEAESepharose chromatography. ItS Km (PEP) was 0. 1 mmol/L with an optimum pH 5. 3, andwas heat-stable and lossed few activity in the range of pH 4. 0-7. 2. Its activity was potently inhibited by Pi. The enzyme was not specific for its substrate, and could hydrolyzea wide variety of phosphate esters. The results indicated that the enzyme was a non-specificacid phosphatase. Various phosphate ester metabolites exhibited additive inhibition effect on it and was competitive with respect to PEP. The enzyme activity was also inhibited byCu2+, Zn2+, and Fe2+, and unaffected by Mg2+, Mn2+, Ca2+, Co2+, and EDTA.