Gagnon C, Harbour D, Camato R
J Biol Chem. 1984 Aug 25;259(16):10212-5.
Protein methylesterase, an enzyme that hydrolyzes protein methyl esters, has been purified. The purification procedure includes ammonium sulfate and acid precipitations, and chromatographies on Sephadex G-100, Polybuffer exchanger 94, and matrex gel Green A. With this procedure, protein methylesterase was purified 1190-fold with a 28% recovery in activity. Its molecular weight has been estimated by polyacrylamide gel electrophoresis under denaturing conditions and by molecular sieving under native conditions at 31,000. Protein methylesterase has an optimum pH of 4.0 and an isoelectric point of 4.45. The enzyme is stable over a wide range of pH (2-10). The Km for ovalbumin methyl esters was estimated at 5.9 microM. Monovalent ions had little effect on activity while divalent ions at concentrations above 50 mM inhibited protein methylesterase activity in a concentration-dependent manner.
蛋白质甲酯酶是一种能水解蛋白质甲酯的酶，现已被纯化。纯化过程包括硫酸铵沉淀、酸沉淀以及在葡聚糖G - 100、聚缓冲液交换剂94和基质凝胶绿A上的色谱分离。通过该方法，蛋白质甲酯酶被纯化了1190倍，活性回收率为28%。其分子量已通过变性条件下的聚丙烯酰胺凝胶电泳和天然条件下的分子筛法估计为31,000。蛋白质甲酯酶的最适pH为4.0，等电点为4.45。该酶在较宽的pH范围（2 - 10）内稳定。卵清蛋白甲酯的米氏常数估计为5.9微摩尔。单价离子对活性影响很小，而浓度高于50毫摩尔的二价离子以浓度依赖的方式抑制蛋白质甲酯酶的活性。
