摘要
为了进一步认识立体选择性转化用菌株近平滑假丝酵母(Candida parapsilosis)SYB-1的转化机理及其转化酶系的酶学特性,考察了该菌种来源的粗酶的辅酶依赖型及立体选择性,发现依赖于辅酶NADP+,该酶将(R)-苯基乙二醇氧化为β-羟基苯乙酮;而依赖于辅酶NADH,该酶不对称还原β-羟基苯乙酮为(S)-苯基乙二醇。在研究该粗酶酶学特性后发现该粗酶对5C的伯醇专一性较强;在包括仲醇和二元醇的手性醇中,对于二元醇的专一性较强;而在还原反应中对2-丁酮专一性较强。金属螯合剂及重金属离子会对该粗酶的活力产生抑制作用。该粗酶催化氧化的最适pH为8.0,最适温度为50℃;催化还原的最适pH为6.0,最适温度为40℃。
The cofactor requirement and the stereospecificity of 1 - phenyl - 1,2 - ethanediol oxidoreduction catalyzed by the crude enzyme from Candida parapsilosis SYB - 1 were investigated. It is indicated that the oxidation of (R) - 1 - phenyl -1,2- ethanediol to the intermediate of β - hydroxyacetophenone was catalyzed by NADP+ - dependent enzyme and the reduction of the intermediate to (S) - 1 - phenyl - 1,2 - ethanediol was catalyzed by NADH - dependent oxidoreductase respectively. After investigating the characteristics of the crude enzyme from C. parapsilosis SYB - 1, it was found that the substrate specificities of this crude enzyme for oxidation were pentanol among primary alcohols and diols among chiral alcohols including secondary alcohols and diols, and that for reduction was 2 - butanone. In addition, the activity of the crude enzyme was enhanced by Zn2+ and inhibited by metal ion chelators and heavy metal ions. The optimum pH for oxidation was 8.0, and that for reduction was 6.0; the optimum temperature for oxidation was 50℃ , and that for reduction was 40 ℃.
出处
《生物加工过程》
CAS
CSCD
2003年第1期66-72,共7页
Chinese Journal of Bioprocess Engineering
基金
江苏省高技术研究计划资助项目(编号:BG2002320)
关键词
辅酶依赖型
立体选择性
氧化还原酶
酶学特性
stereoselectivity
oxidoreductase
cofactor - dependent
enzymatic characteristic
