SUBCELLULAR-LOCALIZATION AND LEVELS OF AMINOPEPTIDASES AND DIPEPTIDASE IN SACCHAROMYCES-CEREVISIAE
SUBCELLULAR-LOCALIZATION AND LEVELS OF AMINOPEPTIDASES AND DIPEPTIDASE IN SACCHAROMYCES-CEREVISIAE
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DOI：
10.1016/0005-2744(78)90253-x
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发表时间：
1978-01-01
期刊：
影响因子：
--
通讯作者：
ROHM, KH
中科院分区：
文献类型：
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作者：
FREY, J;ROHM, KH
S. peptide水解酶（L-aminoacyl L-peptide hydrolases，EC 3.4.11）和一种二肽酶（L-aminoacyl L-amino acid hydrolase，EC 3.4.13）存在于S.啤酒。基于底物特异性和对Zn 2+活化的敏感性的差异，开发了允许在粗细胞提取物中选择性测定这些酶的方法。与孤立的液泡实验表明，氨肽酶I是唯一的酵母肽酶位于液泡室。氨肽酶II（酵母的另一种主要氨肽酶）似乎是一种外部酶，主要位于质膜外。氨肽酶I的合成在含有1%以上葡萄糖的培养基中受到抑制。在氨作为唯一的N源的存在下，其活性与在蛋白胨上生长的细胞相比增强3- 10倍。相反，氨肽酶II和二肽酶的水平不太明显地依赖于生长培养基的组成。显然，氨肽酶II通过在细胞外降解肽来促进氨基酸摄取，而氨肽酶I参与细胞内蛋白质降解。
Three aminopeptidases (L-aminoacyl L-peptide hydrolases, EC 3.4.11) and a single dipeptidase (L-aminoacyl L-amino acid hydrolase, EC 3.4.13) are present in homogenates of S. cerevisiae. Based on differences in substrate specificity and the sensitivity to Zn2+ activation, methods were developed that allow the selective assay of these enzymes in crude cell extracts. Experiments with isolated vacuoles showed that aminopeptidase I is the only yeast peptidase located in the vacuolar compartment. Aminopeptidase II (the other major aminopeptidase of yeast) seems to be an external enzyme, located mainly outside the plasmalemma. The synthesis of aminopeptidase I is repressed in media containing more than 1% glucose. In the presence of ammonia as the sole N source its activity is enhanced 3- to 10-fold when compared to that in cells grown on peptone. In contrast, the levels of aminopeptidase II and dipeptidase are less markedly dependent on growth medium composition. Apparently aminopeptidase II facilitates amino acid uptake by degrading peptides extracellularly, whereas aminopeptidase I is involved in intracellular protein degradation.