摘要:
采用酪蛋白平板透明圈法,结合以鱼粉为底物的蛋白酶活力测定法,从欧洲鳗鲡肠道中分离筛选出1株高产蛋白酶的菌株MJ15。通过形态学观察、Biolog鉴定以及16S rRNA基因序列分析,该菌株鉴定为乳酸乳球菌乳酸亚种Lactococcus lactis subsp. Lactis。对菌株MJ15所产蛋白酶性质进行初步分析,结果显示,其最适作用温度和pH值分别为40℃和5.0,酶的热稳定性以及碱稳定性较差;K+、Na+、Cu2+、Fe2+对蛋白酶有激活作用,但Zn2+、Pepstatin A对该酶有抑制作用;该酶的Km值和Vmax值分别为8.77 mgmL-1和53.48 gmin-1mL-1。
Abstract:
A bacterial strain,MJ15, that secreted high amount of proteases was isolated on a casein plate culture from the intestines of Anguilla anguilla. Activity of the enzyme was determined by using a fishmeal as the substrate for the digestion. By means of morphological observations, biolog identification, and phylogenetic analysis on 16S rRNA sequences,MJ15 was identified as Lactococcus lactis subsp.The activity of the crude protease it secreted peaked at 40℃ and pH 5.0.The thermal and alikali stabilities of the protease were relatively poor. The metal ions, K+, Na+, Cu2+, and Fe2+, enhenced the enzymatic activity, while Zn2+ or pepstatin Aslightly inhibited it.The Kmand Vmaxof the enzyme were determined to be 8.77 mgmL-1 and 53.48 gmin-1mL-1, respectively.
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