GLYCOLYTIC-ENZYMES AND INTERMEDIATES IN CARBON CATABOLITE REPRESSION MUTANTS OF SACCHAROMYCES-CEREVISIAE
GLYCOLYTIC-ENZYMES AND INTERMEDIATES IN CARBON CATABOLITE REPRESSION MUTANTS OF SACCHAROMYCES-CEREVISIAE
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DOI：
10.1007/bf00267449
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发表时间：
1980-01-01
期刊：
影响因子：
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通讯作者：
ZIMMERMANN, FK
中科院分区：
文献类型：
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作者：
ENTIAN, KD;ZIMMERMANN, FK
在C分解代谢抑制部分缺陷的隐性酵母突变体中测定了糖酵解参数。葡萄糖培养细胞中丙酮酸激酶和丙酮酸脱羧酶的比活性比乙醇培养细胞高4 ~ 5倍。基因HEX1突变体在所有培养基上的己糖磷酸化活性降低，而基因HEX2突变体的水平升高，但仅在葡萄糖生长的细胞中。CAT80基因突变体在这方面是正常的。所有突变体的其他糖酵解酶均正常。糖酵解中间体也是如此。只有hex1突变体显示抑制糖的发酵减少。这3个基因显然参与了几种抑制酶的分解代谢抑制，但不是所有的抑制酶。尽管这三种类型的突变体对某些酶的影响有一定的重叠，但它们在作用谱上仍然有明显的不同。C分解代谢物的抑制显然不依赖于糖酵解中间体的单一积累。3个基因的产物HEX1， HEX2和CAT80的活性是触发C分解代谢抑制的直接或间接需要的。即使是C分解代谢抑制的一小部分也是由几个具有调控功能的基因控制的，这表明整个调控回路是高度复杂的。
Glycolytic parameters were determined in recessive yeast mutants with partial defects in C catabolite repression. Specific activities of pyruvate kinase and pyruvate decarboxylase in glucose grown cells of all mutant and wild type strains were 4 5 times higher than in ethanol grown cells. Mutants of gene HEX1 had a reduced hexose phosphorylating activity on all media whereas those of gene HEX2 had elevated levels but only in glucose grown cells. Mutants of gene CAT80 were normal in this respect. All other glycolytic enzymes were normal in all mutants. This was also true for glycolytic intermediates. Only hex1 mutants showed a reduced fermentation of repressing sugars. The 3 genes apparently are involved in catabolite repression of several but not of all repressible enzymes. Even though all 3 types of mutants show a limited overlap in their effects on certain enzymes, they still are distinctly different in their action spectra. C catabolite repression apparently does not depend on the sole accumulation of glycolytic intermediates. The activity of the products of the 3 genes HEX1, HEX2 and CAT80 are required directly or indirectly for triggering C catabolite repression. Even a small segment of C catabolite repression is controlled by several genes with regulatory functions indicating that the entire regulatory circuit is highly complex.