Smulson M E, Rabinovitz M, Breitman T R
J Bacteriol. 1967 Dec;94(6):1890-5. doi: 10.1128/jb.94.6.1890-1895.1967.
O-methylthreonine (OMT), an isosteric analogue of isoleucine, markedly inhibited growth of Escherichia coli 15. This inhibition was overcome most effectively by addition of isoleucine, valine, or leucine to the medium and less effectively by addition of threonine. The dipeptide, valylleucine, also relieved the OMT-induced inhibition but only after a lag period, suggesting that valine and leucine, liberated by dipeptidase action, compete with OMT for entry into the cell. OMT was activated and transferred to transfer ribonucleic acid (RNA) by isoleucyl-RNA synthetase in vitro. The rate of OMT incorporation into protein of intact cells was comparable to that of isoleucine. In contrast to isoleucine, very high concentrations of OMT were required to inhibit threonine deaminase, and the inhibition was strictly competitive with threonine. In addition, OMT inhibited a threonine deaminase preparation desensitized to isoleucine inhibition.
O-甲基苏氨酸（OMT）是异亮氨酸的等排类似物，能显著抑制大肠杆菌15的生长。向培养基中添加异亮氨酸、缬氨酸或亮氨酸能最有效地克服这种抑制作用，而添加苏氨酸的效果则较差。二肽缬氨酰亮氨酸也能缓解OMT诱导的抑制作用，但有一段延迟期，这表明二肽酶作用释放出的缬氨酸和亮氨酸与OMT竞争进入细胞。在体外，异亮氨酰-转运核糖核酸（RNA）合成酶能激活OMT并将其转移至转运RNA。完整细胞中OMT掺入蛋白质的速率与异亮氨酸相当。与异亮氨酸不同，抑制苏氨酸脱氨酶需要非常高浓度的OMT，且这种抑制作用与苏氨酸严格竞争。此外，OMT还能抑制对异亮氨酸抑制作用脱敏的苏氨酸脱氨酶制剂。
