摘要
研究了微生物Aspergillus oryzaec42菌株产特异的柴胡皂苷糖苷酶的分离纯化及其酶学性质.结果表明,该酶能够水解柴胡皂苷A或柴胡皂苷B2侧链的3-O-β-(1→3)-Glc和3-O-β-Fuc,其分子量约为58000.柴胡皂苷糖苷酶首先水解柴胡皂苷A或B2侧链的3-O-β-(1→3)-Glc生成3-O-β-Fuc-柴胡皂苷元A或B2,然后进一步水解3-O-β-Fuc-柴胡皂苷元A或B2的3-O-β-Fuc生成柴胡皂苷元A或B2.柴胡皂苷糖苷酶的最适反应温度为4℃,最适pH值为5.0;Na+和K+对酶活力的影响不明显;Cu2+,Hg2+和Ag+对酶活力有显著的抑制作用;Ca2+和Mg2+对酶活力有轻微的激活作用.
Radix bupleuri,a well-known traditional Chinese herb-drug,is often used to treat common cold with fever.One of the major physiologically active ingredients in radix bupleuri is saikosaponin which has the properties of anti-inflammation,anti-hypersusceptibility,anti-thrombus.The natural structures of saikosaponins are not suitable for physiological or pharmacological effects,the enzymatic transforming generally improves the bioactivity of natural productions.In this paper,a new special saikosaponin-glycosidase hydrolyzing 3-O-β-(1→3)-glucoside and 3-O-β-fucoside of saikosaponin A or B2 was isolated from Aspergillus oryzae c42 strain,purified and characterized.The methods of centrifugation,ammonium sulfate precipitation,ion-exchange chromatography on DEAE-cellulose column and vertical slab polyacrylamide gel electrophoresis(PAGE) were used to purify the enzyme,and its partial characteristics were studied.The molecular weight of saikosaponin-glycosidase was about 58000 by SDS-PAGE.The enzyme hydrolyzed 3-O-β-(1→3)-glucoside of saikosaponin A or B2 into 3-O-β-fucoside-saikosapogenin A or B2,and further hydrolyzed 3-O-β-fucoside of 3-O-β-fucoside-saikosapogenin A or B2 into their aglycone(saikosapogenin A or B2) exhibiting significant differences from all previously reported glycosidases.The optimum temperature of the saikosaponin-glycosidase was 40 ℃;the optimum pH was 5.0.The activity of this enzyme was not apparently affected by Na+ and K+ ions,but it was significantly inhibited by Cu2+,Hg2+ and Ag+ ions;and slightly affected by Ca2+ and Mg2+ ions.Further study on saikosaponin-glycosidase will bring new insight to the understanding of glycosidases.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2010年第6期1152-1157,共6页
Chemical Journal of Chinese Universities
基金
国家自然科学基金(批准号:30371744
20476017)
辽宁省教育厅高等学校创新团队项目(批准号:2007T006
2008T008)资助