Kjellin-Stråby K
J Bacteriol. 1969 Nov;100(2):687-94. doi: 10.1128/jb.100.2.687-694.1969.
Methionine auxotrophs of Saccharomyces cerevisiae continue to synthesize ribonucleic acid (RNA) after methionine withdrawal. The newly synthesized transfer RNA (tRNA) is methyl-deficient in some strains, but not in all. Whether such tRNA will accumulate depends on the position of the block in the methionine pathway that is carried by the mutant strain. Free methionine rapidly decreases in the intracellular pool of all strains after its removal from the medium. Certain metabolites derived from methionine are removed from the pool relatively slowly after methionine withdrawal. Notable among these is S-adenosylhomocysteine, which is depleted less rapidly from those strains that accumulate methyl-deficient tRNA than from others. S-adenosylhomocysteine is a potent inhibitor of tRNA-methylating enzymes in vitro.
酿酒酵母的甲硫氨酸营养缺陷型菌株在甲硫氨酸撤除后仍继续合成核糖核酸（RNA）。新合成的转运RNA（tRNA）在某些菌株中甲基化不足，但并非所有菌株都如此。这种tRNA是否会积累取决于突变菌株在甲硫氨酸途径中阻断的位置。从培养基中去除甲硫氨酸后，所有菌株细胞内池中的游离甲硫氨酸迅速减少。甲硫氨酸撤除后，某些由甲硫氨酸衍生的代谢物从池中清除的速度相对较慢。其中值得注意的是S-腺苷同型半胱氨酸，与其他菌株相比，从积累甲基化不足tRNA的菌株中消耗的速度较慢。S-腺苷同型半胱氨酸在体外是tRNA甲基化酶的有效抑制剂。
