5-氟尿苷生物转化率的影响因素研究

目的:利用产气肠杆菌EAM-Z1转化合成5-氟尿苷(5-FUR),并对影响5-FUR转化率的因素进行了考察。方法:以磷酸盐缓冲液(PBS)为溶剂的5-FUR的转化率为对照,考察反应溶剂Na2SO4溶液、中间体稳定剂、金属离子、固定化细胞、粗酶液等因素对转化率的影响。结果:以Na2SO4溶液为溶剂进行转化,转化率可提高10%左右;双中间体稳定剂硼砂+硼酸使转化率提高20%左右;Mg2+和Zn2+可提高产物的转化率,在以PBS为溶剂的转化反应中,1 mmol/L Mg2使转化率提高了11.31%,以Na2SO4溶液为溶剂的转化反应中,4 mmol/L Zn2+使转化率提高了9.43%;以固定化细胞进行生物转化,反应时间缩短为1 h,但转化率略有降低;以粗酶液进行生物转化,反应时间为4 h,转化率提高21.29%。结论:5-FUR的转化率受多种因素的影响,合理的反应溶剂如Na2SO4溶液、中间体稳定剂、金属离子、提取酶粗提液等方法均可以较显著的提高5-FUR的转化率。

Factors affecting the conversion rate of 5-fluorouridine

Aim:To evaluate the factors affecting the conversion rate of 5-fluorouridine(5-FUR) in Enterobacter aerogenes, and provide instructions to the laboratory research and the industrial production.Methods: While the conversion rate of 5-FUR based upon the experimentation in the phosphate buffer(PBS) was used as control,we studied the effects on the conversion rate of the variables such as Na_2SO_4 media,intermediate stabilizers,metal ions,immobilized cells,and the crude enzyme.Results:Compared to the control,it was found that the conversion rate in the media of Na_2SO_4 and in the presence of the intermediate stabilizers,borax plus boric acid increased around 10% and 20%,respectively.The ions,Mg~(2+) and Zn~(2+) also enhanced the conversion rate.The conversion rate,in the PBS solvent of 1 mmol/L Mg~(2+),increased by 11.31% while the rate increased by 9.43% in the Na_2SO_4 solvent of 4 mmol/L Zn~(2+).Moreover,in the biotransformation investigations using immobilized cells,the reaction time decreased to 1 h with a slight decrease in conversion rate.On the other hand,the rate of the biotransformation in the matrix of crude enzyme increased by 21.29% in 4 hours.Conclusion:The conversion rate of 5-FUR was influenced by the observed variables.The media such as Na_2SO_4,intermediate stabilizers,metal ions and the crude enzyme could contribute to the enhancement in the conversion rate of 5-FUR.