酿酒酵母蛋氨酸营养缺陷型和野生型菌株中的胱硫醚代谢
Cystathionine metabolism in methionine auxotrophic and wild-type strains of Saccharomyces cerevisiae.
作者信息
Sorsoli W A, Buettner M, Parks L W
出版信息
J Bacteriol. 1968 Mar;95(3):1024-9. doi: 10.1128/jb.95.3.1024-1029.1968.
The role of cystathionine in methionine biosynthesis in wild-type and auxotrophic strains of Saccharomyces cerevisiae was studied. Homocysteine and cysteinerequiring mutants were selected for detailed study. Exogenously supplied cystathionine, although actively transported by all strains tested, could not satisfy the organic sulfur requirements of the mutants. Cell-free extracts of the wild-type, homocysteine, and cysteine auxotrophs were shown to cleave cystathionine. Pyruvic acid and homocysteine were identified as teh products of this cleavage. A mutant containing an enzyme which could cleave cystathionine to homocysteine in cell-free experiments was unable to use cystathionine as a methionine precursor in the intact organisms. The significance of this finding is discussed.
研究了胱硫醚在酿酒酵母野生型和营养缺陷型菌株蛋氨酸生物合成中的作用。选择了需要高半胱氨酸和半胱氨酸的突变体进行详细研究。尽管所有测试菌株都能主动转运外源提供的胱硫醚，但它不能满足突变体对有机硫的需求。野生型、高半胱氨酸和半胱氨酸营养缺陷型的无细胞提取物可裂解胱硫醚。丙酮酸和高半胱氨酸被鉴定为这种裂解的产物。在无细胞实验中，含有能将胱硫醚裂解为高半胱氨酸的酶的突变体，在完整生物体中不能将胱硫醚用作蛋氨酸前体。讨论了这一发现的意义。
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