Chandler J L, Gholson R K
J Bacteriol. 1972 Jul;111(1):98-102. doi: 10.1128/jb.111.1.98-102.1972.
The excretion of quinolinic acid was studied in growing and resting cells of Escherichia coli K-12 nadC(13). Under optimal conditions, this organism could synthesize quinolinic acid in several-fold excess of the amount which would be required for normal growth. The excretion of quinolinic acid was controlled by the concentration of nicotinamide adenine dinucleotide (NAD) precursors available to the organism either during growth or during incubation in dense cell suspensions. These observations suggest that biosynthesis of NAD de novo is regulated by both repression and feedback inhibition. Analogues of niacin which inhibit bacterial growth also inhibited and repressed the synthesis (excretion) of quinolinic acid. The pH optimum for quinolinic acid excretion agreed favorably with the optimum observed for its synthesis in vitro. The rate of quinolinic acid excretion was strongly influenced by the concentration of ribose or glycerol in the medium.
在大肠杆菌K - 12 nadC(13)的生长细胞和静止细胞中研究了喹啉酸的排泄情况。在最佳条件下，这种生物体能够合成的喹啉酸量比正常生长所需量高出数倍。喹啉酸的排泄受生物体在生长期间或在高密度细胞悬液中孵育期间可利用的烟酰胺腺嘌呤二核苷酸（NAD）前体浓度的控制。这些观察结果表明，从头合成NAD的生物合成受阻遏和反馈抑制的调节。抑制细菌生长的烟酸类似物也抑制并阻遏了喹啉酸的合成（排泄）。喹啉酸排泄的最适pH与体外合成时观察到的最适pH非常吻合。喹啉酸的排泄速率受培养基中核糖或甘油浓度的强烈影响。
