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以L-半胱氨酸和吲哚为底物酶法合成L-色氨酸

韦平和, 吴梧桐   

  1. 中国药科大学生物制药学院, 南京 210009
  • 收稿日期:1998-10-26 修回日期:1999-09-10 出版日期:1999-12-15 发布日期:1999-12-15

Enzymatic Synthesis of L-Tryptophan from L-Cysteine and Indole

Wei Pinghe, Wu Wutong   

  1. School of Biopharmaceutics, China Pharmaceutical University Nanjing 210009
  • Received:1998-10-26 Revised:1999-09-10 Online:1999-12-15 Published:1999-12-15

摘要: L-半胱氨酸和吲哚为底物, 利用色氨酸酶基因工程菌WW-11酶法合成L-色氨酸。方法:IPTG诱导基因工程菌色氨酸酶表达, 将酶活最高时的工程菌游离细胞作为转化反应的酶源, 通过纸层析和氨基酸自动分析仪分析并测定转化液中L-色氨酸的含量。结果: 80mL反应液(L-半胱氨酸0.75g,吲哚0.75g)37℃反应48h, 可积累L-色氨酸1.18g, L-半胱氨酸转化率为93.2%, 吲哚转化率为90.1%。经分离纯化所得的L-色氨酸晶体, 在熔点、旋光性和红外吸收光谱等方面与标准品完全一致。结论: 色氨酸酶基因工程菌能有效地催化L-半胱氨酸和吲哚合成L-色氨酸,这种酶合成法是工业化生产L-色氨酸较为有效的方法之一。

关键词: L-半胱氨酸, L-色氨酸, 色氨酸酶基因工程菌, 合成

Abstract: Objective: L-Tryptophan was enzymatically synthesized by tryptophanase in genetic engineering strain WW-11 from L-cysteine and indole. Methods:Tryptophanase in engineeringstrain was expressed by IPTG induction. The engineering strain free cells with the highest enzymeactivity were used as enzyme source in the reaction mixture. L-Tryptophan accumulated in the reaction mixture was analysed and determined by paper chromatography and amino acid analyzer Results:An yield of 1.18g of L-tryptophan was obtained from 0.75 g of L-cysteine and 0.75g of indolein 80 mL reaction mixture shaking for 48 h at 37 ℃. The conversion rate was 93.2% for L-cysteineand 90.1% for indole. After isolation and purification, the crystals were identical with authentic Ltryptophan, in respects of melting point, optical activity and IR-spectrum. Conclusion:Tryptophanase in genetic engineering strain could effectively catalyze L-cysteine and indole tosynthesize L-tryptophan. This enzymatic synthesis method is one of the more effective methods forthe industrial production of L-tryptophan.

Key words: L-Cysteine, L-Tryptophan, Tryptophanase genetic engineering strain, Synthesis

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