摘要
目的：以Ｌ丝氨酸和吲哚为底物，用色氨酸酶基因工程菌酶法合成Ｌ色氨酸。方法：以ＩＰＴＧ 诱导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，通过纸层析分析并测定转化液中Ｌ色氨酸的含量。结果：１００ｍｌ 反应液（Ｌ丝氨酸３ｇ ，吲哚３ｇ）３７ ℃反应４８ｈ 可积累Ｌ色氨酸４ ．９ｇ ，Ｌ丝氨酸转化率为８４ ．２ ％ ，吲哚转化率为９３ ．６ ％ 。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丝氨酸和吲哚合成Ｌ色氨酸，进一步证明了该酶在Ｌ色氨酸酶法合成中的可行性和有效性。
OBJECTIVE:L Tryptophan was enzymatically synthesized by tryptophanase with the substrates of L serine and indole in genetic engineering strain.METHOD:Tryptophanase was expressed in engineering strain which was induced by IPTG.The engineering strain free cells with the highest enzyme activity were used as enzyme source in the conversion reaction mixture.L Tryptophan accumulated in the reaction mixture was analyzed and determined by paper chromatography.RESULTS:4.9g of L Tryptophan was formed from 3g of L serine and 3g of indole in 100ml reaction mixture shaken for 48h at 37℃.The conversion rate was 84.2% for L serine and 93.6% for indole.After isolating and purificating,the crystals were identical to authentic L Tryptophan,in respects of melting point,optical activity and IR spectra.CONCLUSION:Tryptophanase expressed in genetic engineering strain could efficiently catalyze L serine and indole to synthesize L Tryptophan,and the feasibility and efficiency of tryptophanase in this enzymatic synthesis were confirmed.
出处
《中国现代应用药学》
CAS
CSCD
1999年第6期37-39,共3页
Chinese Journal of Modern Applied Pharmacy
关键词
色氨酸酶
基因工程菌
L-色氨酸
合成
tryptophanase genetic engineering strain,L tryptophan,L serine,conversion
