摘要
利用重组E.coli产天冬氨酸酶和天冬氨酸转氨酶催化生产L-4-氧苯丙氨酸的工艺。实验结果表明最佳转化条件为-37℃,pH值4.5—8.5,菌体与酮酸的质量浓度比为1.5,CTAB的质量分数为0.04%,酮酸的质量浓度11.28g/L,富马酸铵与酮酸的摩尔比为3.0:1.0,添加1mmol/L的Fe^2+,L-天冬氨酸与酮酸的摩尔比为0.4:1。在最适条件下,经过14h酶转化反应达到平衡,酮酸转化率可达到95%以上,L-4-氟苯丙氨酸得率也可达到80%以上。此法原料简单易得,为L-4-氟苯丙氨酸的制备提供了一种新方法:
Preparation of L-4-fluorophenylalanine catalyzed by aspartate ammonia-lyase and aspartate aminotransferase from a recombinont strain of E. coli was studied. At first step, fumaric acid turned into L- aspartic acid as the donor of ammonia group for further reaction, catalyzed by aspartate ammonia-lyase. With the ammonia donor 4-fluorophenylpyruvate was converted to L-4-fluorophenylalanine catalyzed by aspartate aminotransferase. After 14 h, the bioconversion of 4-fluorophenylpyruvate was over 95% and the yield of L-4-fluorophenylalanine could be above 80% under the optimal conditions as follows : 37 ℃ , pH value range of 4.5 - 8.5, 1.5 of the mass ratio of cell to 4-fluorophenylpyruvate, 0. 04% of the mass ratio of CTAB, 11.28 g/L of the 4-fluorophenylpyruvate concentration, n ( ( NH4 ) 2 Fuma) : n (4-fluorophenylpyruvate) = 3.0: 1, lmmol/L Fe^2+ , and n(L-Asp) : n(4-fluorophenylpyruvate) = 0. 4: 1. The raw materials of this preparation were cheap and easy to obtain.
出处
《生物加工过程》
CAS
CSCD
2007年第3期52-57,共6页
Chinese Journal of Bioprocess Engineering
基金
国家973项目(2003CB716004)
国家自然科学重点基金资助项目(20336010)
关键词
酶法
L-4-氟苯丙氨酸
对氟苯丙酮酸
天冬氨酸酶
天冬氨酸转氨酶
Enzymatic method
L-4-fluorophenylalanine
4-fluorophenylpyruvate
aspartate ammonialyase
aspartate aminotransferase