Studies on compartmentation of S-adenosyl-L-methionine in Saccharomyces cerevisiae and isolated rat hepatocytes.
Studies on compartmentation of S-adenosyl-L-methionine in Saccharomyces cerevisiae and isolated rat hepatocytes.
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DOI：
10.1016/0304-4165(83)90060-0
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发表时间：
1983-06
期刊：
影响因子：
--
通讯作者：
Jamal Farooqui;Hyang Woo Lee;Sangduk Kim;Woon Ki Paik
中科院分区：
文献类型：
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作者：
Jamal Farooqui;Hyang Woo Lee;Sangduk Kim;Woon Ki Paik
研究了酿酒酵母和分离的大鼠肝细胞中代谢不同的 S-腺苷-L-甲硫氨酸库的存在。利用[甲基-14 C]蛋氨酸相对较长的标记周期，对代谢“稳定”的池进行标记。随后用 [methyl-3 H] 蛋氨酸进行简短标记，选择性地标记了假定的代谢“不稳定”库。这些可区分池的存在是通过在含有环霉素的无标记培养基中追踪期间追踪S-腺苷-L-甲硫氨酸中的 3 H 和 14 C 标记消失来确定的，以防止 S-腺苷-L-甲硫氨酸的进一步合成。在酵母和肝细胞中，S-腺苷-L-甲硫氨酸中的3 H 14 C比率急剧下降。 S-腺苷-L-甲硫氨酸的个体3H和14C降低显示酵母的t 1 2 值为3和8分钟，肝细胞的t 1 2值为4和18分钟。结果强烈表明，两个系统中实际上确实存在至少两个代谢上不同的 S-腺苷-L-甲硫氨酸库。亚细胞分级分离显示，酵母和肝细胞的细胞质中都存在“不稳定”库，而酵母和肝细胞的液泡和线粒体部分中分别存在“稳定”库。还在厌氧追逐条件下的正常酵母和小型突变酵母中研究了 S-腺苷-L-甲硫氨酸池。与有氧追逐的正常酵母形成鲜明对比，两者都显示出S-腺苷-L-甲硫氨酸的3H和14C密切平行的减少。
The existence of metabolically distinct pools of S-adenosyl-L-methionine in Saccharomyces cerevisiae and isolated rat hepatocytes was investigated. Utilizing a relatively long labeling period with [methyl-14 C] methionine, a metabolically ‘stable’pool was labeled. A subsequent short labeling with [methyl-3 H] methionine selectively labeled a putative metabolically ‘labile’pool. The existence of these distinguishable pools was ascertained by following the 3 H and 14 C label disappearance in S-adenosyl-L-methionine during the chase-period in label-free media containing cycloleycine to prevent futher synthesis of S-adenosyl-L-methionine. In both yeast and hepatocytes, the 3 H 14 C ratio in S-adenosyl-L-methionine decreased sharply. The individual 3 H and 14 C decrease in S-adenosyl-L-methionine showed t 1 2 values of 3 and 8 min for yeast and 4 and 18 min for hepatocytes. The results strongly indicate that at least two metabolically distinct S-adenosyl-L-methionine pools actually do exist in both systems. Subcellular fractionation revealed that the ‘labile’pool exist in the cytosol for both yeast and hepatocytes while the ‘stable’pool exists in the vacuolar and the mitochondrial fraction for the yeast and hepatocytes respectively. The S-adenosyl-L-methionine pools were also studied in normal yeast under anaerobic chase condition and petite mutant yeast. Sharply contrasting with aerobically chased normal yeast, both showed closely parallel 3 H and 14 C decreases in S-adenosyl-L-methionine.