摘要
为获得高效降解卡拉胶菌株,从青岛太平角海域采集的角叉菜表面分离到1株高产κ-卡拉胶酶的海洋交替假单胞菌（Pseudoalteromonas sp.）QY202,经硫酸铵沉淀、脱盐、DEAE阴离子交换层析等步骤从该菌株发酵液上清中分离纯化得到1种专一性降解κ-卡拉胶的κ-卡拉胶酶,并研究了该酶的基本酶学性质。结果表明该酶被纯化了23.1倍,回收率为43.9%,分子量大小为33.2 kDa。酶的最适反应温度为40℃,最适反应pH为8.0,在0-40℃,pH=7.0-8.0之间酶活力较稳定。酶对底物κ-卡拉胶的米氏常数Km值为1.6 mg/mL。Na^＋、K^＋对酶活有促进作用,而Hg^2＋、Cu^2＋强烈抑制酶的活性。酶解κ-卡拉胶的主产物为硫酸新κ-卡拉二糖和硫酸新κ-卡拉四糖。
A marine bacterium Pseudoalteromonas sp.QY202 with high κ-carrageenase activity was isolated from the surface of Chondrus crispus.The κ-carrageenase was purified to electrophoretic homogeneity from the culture supernatant by a procedure of ammonium sulfate precipitation,desalting and DEAE-sepharose ion exchange chromatography,and the characterization of the enzyme was studied.The results show that the enzyme is purified 23.1 folds with a total recovery yield of 43.9% and gives a single band on SDS-PAGE with a molecular mass of 33.2 kDa.The optimum temperature and pH for enzyme activity are 40 ℃ and pH8.0,respectively.The enzyme is stable at temperatures below 40 ℃ and over a range of pH7.0-8.0.For κ-carrageenan,the enzyme gave a Km value of 1.6 mg/mL.The enzyme activity could be enhanced by the presence of Na＋ and K＋,whereas enormously inhibited by Hg^2＋and Cu^2＋.The main hydrolysis products of κ-carrageenan by the enzyme are κ-neocarradiaose and κ-neocarratetraose.
出处
《中国海洋大学学报（自然科学版）》
CAS
CSCD
北大核心
2010年第3期95-100,共6页
Periodical of Ocean University of China
基金
国家高技术研究发展计划项目(2007AA091506)
青岛市科技攻关项目(05-2-JC-56)资助
