摘要
目的:得到纯化的无花果沙雷氏菌CH02503的壳聚糖酶,并研究其生化性质.方法:将发酵粗酶液先后通过硫酸铵分级沉淀,superdex75凝胶柱和羧甲基纤维素离子交换柱层析,壳聚糖酶得到纯化.结果:经测定,该酶为内切酶,其相对分子质量为29kDa,等电点9.4,在45℃和pH 4.0～7.5之间稳定,最适温度是45℃,最适pH3.6,Mn2+、Co2+能够激活,pb2+、Cu2+、Ni+、Cr3+能够抑制该酶的活性,该酶最适底物是脱乙酰度85%的壳聚糖,对脱乙酰度低于45%的壳聚糖不能作用,对羧甲基甲壳素和羧甲基纤维素不能作用,以完全脱乙酰的壳聚糖为底物时,最终水解产物是单糖、二糖、三糖,反应的米氏常数为0.44mg/ml.
Objective：to purify and characterize the chitosanase from Serratia ficaria CH0203. Methods： Purification of the chitosanase was achieved successively by ammonia sulphate fractional precipitation, superdex75 column chromatography and carboxymethyl cellulose column chromatography. Results：It is an endo- splitting chitosanase, molecular weight 29 kDa and isoelectric point 9.4. The chitosanase was stable below 45℃ and within the pH range from 4.0 ～ 7.5. Its optimal reaction temperature was 45℃ and optimal reaction pH was 3.6. Mn^2＋ , Co^2＋ activate and Pb^2＋ ,Cu^2＋ ,Ni^2＋ ,Cr^3＋ inhibited its activity. The chitosanase acts most effectively on 85% deacetylated chitosan, and can＇t act on chitosan deacetylated lower than 45 %, neither on carboxymethyl chitin or carbexymethyl cellulose. The final hydrolysates are monomer, dimer and tfimer when the 100% deacetylated chitosan is used as substrate and its michaelis constant was 0.44mg/ml.
出处
《生物技术》
CAS
CSCD
2005年第6期24-27,共4页
Biotechnology
作者简介
段杉（1966-），男，博士，副教授，研究方向：食品酶学；
彭志英（1934），男，教授，博士生导师，研究方向：食品生物技术。
