摘要
用丙酮将草鱼肠脱脂，磷酸盐缓冲溶液提取粗酶液，再用10％-40％饱和度的硫酸铵分级沉淀制取粗草鱼消化道碱性蛋白酶。粗草鱼碱性蛋白酶的比活力为2800U／g，最适作用温度为37℃，最适作用pH为10．3。在50℃保温30min后还保留60％以上的酶活力，要使其损失约80％的活力，需要在60℃保温30min。50mmol／L的甲苯磺酰赖氨酸氯甲酮（TLCK）、甲苯磺酰氟（PMSF）和50μmol／L大豆胰蛋白酶抑制因子（SBTI）分别抑制78．92％、75．98％和80．23％的酶活力。SDS-底物-聚丙烯酰胺凝胶电泳表明碱性蛋白酶的活性成分有4种，一种为非丝氨酸蛋白酶，相对分子质量为105000；另外三种为胰蛋白酶，相对分子质量分别为26400、30750和43000。
The intestine of grass carp （ Ctenopharyngodon idellus ） was defatted with cold acetone , then extracted with phosphate buffer of pH 7.0 .The obtained supernatant was precipitated at 10%-40% of ammonium sulfate saturation, and a crude alkaline protease product was obtained. The crude alkaline protease had the specific activity of 2800U/g, optimum temperature of 45℃ and optimun pH of 10.3,when hydrolyzing casein. It lost 40% and 80% of activity after incubation for 30 min at 50℃ and 60℃,respectively. 78. 92% ,75.98% and 80.23% of its activity were inhibited after incubated with 50 mmol/L tosyl-lysine chloromethyl kotone （TLCK）, phenylmethylsulfonylfluoride （PMSF） and 50μmol/L soybean trypsin inhibitor （SBTI）, respectively. SDS-substrate-PAGE （Sodium dodecyl sulfate-substrate-Polyacrylamide gel electrophoresis） showed that there were four sorts of alkaline proteases in the crude grass carp extract. Among them, three sorts were serine proteases （trypsins）. The other was not serine protease. Their relative molecular masses were 26400, 30750, 43000 and 105000, respectively.
出处
《广西农业生物科学》
CSCD
2007年第3期221-226,共6页
Journal of Guangxi Agricultural and Biological Science
基金
湖南省教育厅资助项目(02C580)
