乌贼墨多酚氧化酶的部分特性

Some properties of polyphenol oxidase from cuttlefish (Sepia esculenta Hoyle) ink

以乌贼墨为材料,用0.05mol/L pH7.2的磷酸盐缓冲液提取多酚氧化酶(PPO),30％～80％的硫酸铵分级沉淀后通过DEAE-Sepherose CL-6B层析柱分离,合并具有较高酶活性的洗脱液,透析、浓缩后用于酶的特性研究。通过金属离子对该酶活性影响的研究表明,在mmol/L水平,铜离子和铅离子对该酶具有强烈抑制作用,但铜离子在20μmol/L浓度时,对酶却有显著激活作用。在mmol/L水平,Na^+、K^+、Mg^(2+)和 Ca^(2+)对PPO活性无显著影响。在无机阴离子中HSO_3^-对酶活性有强烈抑制作用,在10mmol/L时抑制效率达100％,而Cl^-、Br^-、I^-和SO_4^(2-)则对PPO活性无显著影响。

Polyphenol oxidase(PPO) was extracted from cuttlefish ink with 0.05mol/L pH 7.2 sodium phosphate extraction buffer. The crude extract was fractionated with solid ammonium sulfate of 30% - 80% saturation. After dialysis and concentration, The enzyme solution was purified by DEAE-Sepharose CL-6B column chromatography and a 12.2 fold purification of PPO was obtained. Cu2+ and Pb2+ at level of mmol/L inhibited PPO activity while Na+ , K+ , Mg2+ and Ca2+ have little effect on PPO activity, however PPO was apparently activated by Cu2+ at 20umol/L. PPO activity was strongly inhibited by HSO3 ~ and the activity was completely inhibited at 10mmol/L. Cl- , Br~ , I- and SO42- have almost no effect on PPO activity.