丝氨酸
苏氨酸
高丝氨酸
大肠杆菌
半胱氨酸
化学
生物化学
立体化学
异亮氨酸
酶
分子生物学
生物
氨基酸
亮氨酸
群体感应
毒力
基因
作者
Hiroko Hama,Takashi Kayahara,Masaaki Tsuda,Tomofusa Tsuchiya
标识
DOI:10.1093/oxfordjournals.jbchem.a123427
摘要
We have reported that a major cause of growth inhibition of Escherichia coli by L-serine is its inhibition of homoserine dehydrogenase I (HDH I), which is involved in the biosyntheses of threonine and isoleucine [Hama, H., Sumita, Y., Kakutani, Y., Tsuda, M., & Tsuchiya, T. (1990) Biochem. Biophys. Res. Commun. 168, 1211–1216]. However, Patte et aL reported that L-serine does not inhibit HDH I [Patte, J.-C, Truffa-Bachi, P., & Cohen, G.N. (1966) Biochim. Biophys. Acta 128, 426–439]. In studies on the reason for these discrepant results, we found that the concentration of K+ and the pH in the assay mixture strongly influenced the inhibitory effect of L-serine. L-Serine strongly inhibited the HDH I activities in both the forward and reverse reactions between aspartate semialdehyde and homoserine at a physiological K+ concentration (100 to 200 mM) and physiological pH (7.5) for E. coli cells. On the other hand, two well-known inhibitors of HDH I, L-threonine and L-cysteine, strongly inhibited the activity regardless of the K+ concentration and pH.
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