The expression, purification and activity detect of quinolinic acid phosphoribosyl transferase and nicotinic acid phosphoribosyl transferase from Escherichia coli
大肠杆菌来源的喹啉酸磷酸核糖转移酶和烟酸磷酸核糖转移酶的表达纯化及酶活性的初步检测

Objective] The expression, purification of quinolinic acid phosphoribosyl transferase (QPRT) and nicotinic acid phosphoribosyl transferase (NaPPT) from Escherichia coli (E. coli) were undertaken in prokaryotic expression system and activity detection of QPRT and NaPPT in vitro. Methods] The NadC encoding QPRT and PncB encoding NaPPT were cloned and then ligated into pET28a and pRSETB to generate the expression plasmid pET28a-NadC and pRSETB-PncB, respectively. The plasmids were expressed in E. coli BL21(DE3) and enzymes were purified in vitro. Enzymes activity were detected by analyzing the reaction mixture on a high performance liquid chromatography (HPLC) system. Results] QPRT and NaPPT were expressed and purified, the results indicate that quinolinic acid can be transformed into nicotinic acid through regioselective decarboxylation catalyzed by recombinant QPRT and NaPPT sequentially.