摘要
利用L-半胱氨酸脱巯基酶实现DL-半胱氨酸的拆分.将前期构建的含有恶臭假单胞菌TS1138菌株的L-半胱氨酸脱巯基酶基因的基因工程菌E.coli BL21(DE3)-pET21a(+)-CD进行诱导表达,测定其酶活力为126.5 U/g.以该菌体为酶源,考查DL-半胱氨酸拆分条件,确定其最佳pH为9.0,最佳反应温度为45℃,最佳底物浓度6 g/L,最佳菌体浓度为10 g/L,最佳反应时间为1 h.在该条件下拆分DL-半胱氨酸,并将D-半胱氨酸氧化为D-胱氨酸,1 L催化反应体系可获得1.86 g D-胱氨酸,收率为64.6%,经HPLC测定其纯度为98.7%.为D-胱氨酸及D-半胱氨酸提供了一条新的绿色生产途径,具备一定的产业化前景.
One novel method is established to resolute DL-cysteine via L-cysteine desulfhydrase.L-cysteine desulfhydrase encoding gene,originated from Pseudononas putida TS1138 strain,was subcloned in plasmid pET-21a（＋） and expressed in E.coli BL21（DE3）.After the induction of IPTG,the enzymatic activity of E.coli pellet was measured as 126.5 U/g.Using E.coli pellet as crude enzyme,the resolution conditions were optimized： at pH 9.0 and 45 ℃,at a substrate concentration of 6 g/L and E.coli concentration of 10 g/L,the best yield can be achieved within one hour of reaction.Under such conditions,the resolution of DL-cysteine was performed,and 1.86 g of D-cystine was obtained with a yield of 64.6%.The purity of D-cystine was further confirmed by HPLC as 98.7%.This study provides one new method for the preparation of D-cysteine and D-cystine.
出处
《南开大学学报（自然科学版）》
CAS
CSCD
北大核心
2011年第5期82-87,共6页
Acta Scientiarum Naturalium Universitatis Nankaiensis
基金
天津市重大项目(09ZCKFSH00900)
