CHARACTERIZATION OF PDC6, A 3RD STRUCTURAL GENE FOR PYRUVATE DECARBOXYLASE IN SACCHAROMYCES-CEREVISIAE
CHARACTERIZATION OF PDC6, A 3RD STRUCTURAL GENE FOR PYRUVATE DECARBOXYLASE IN SACCHAROMYCES-CEREVISIAE
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DOI：
10.1128/jb.173.24.7963-7969.1991
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发表时间：
1991-12-01
影响因子：
3.2
通讯作者：
HOHMANN, S
中科院分区：
文献类型：
--
作者：
HOHMANN, S
丙酮酸脱羧酶是酵母酒精发酵的关键酶。两个结构基因，PDC 1和PDC 5的特点。缺失这些基因中的任何一个对丙酮酸脱羧酶的特异性活性几乎没有影响，但在缺失PDC 1和PDC 5的突变体中检测不到酶活性（S. Hohmann和H.欧洲塞德伯格188：615-621，1990）。在这里，我描述了PDC 6，一个在结构上与PDC 1和PDC 5密切相关的基因。PDC 6的产物似乎不是葡萄糖培养基中野生型丙酮酸脱羧酶活性所需的; DELTA-pdc 6突变体没有降低的特异性酶活性，并且PDC 6缺失没有改变缺乏其他两个结构基因中的一个或两个的突变体的表型或特异性酶活性。然而，在乙醇培养基中生长的细胞中，PDC 6缺失导致丙酮酸脱羧酶活性降低。北方（RNA）印迹分析显示，PDC 6弱表达，并且在乙醇培养基中生长期间表达似乎更高。由于丙酮酸脱羧酶催化的是不可逆反应，因此这种行为仍然不清楚。PDC结构基因缺失突变体的所有组合，产生不同量的丙酮酸脱羧酶活性的表征表明，该酶也是在半乳糖和乙醇培养基中正常生长所需的，特别是对于在乙醇培养基上萌发的孢子的适当生长起始。
Pyruvate decarboxylase is the key enzyme in alcoholic fermentation in yeast. Two structural genes, PDC1 and PDC5 have been characterized. Deletion of either of these genes has little or no effect on the specific pyruvate decarboxylase activity, but enzyme activity is undetectable in mutants lacking both PDC1 and PDC5 (S. Hohmann and H. Cederberg, Eur. J. Biochem. 188:615-621, 1990). Here I describe PDC6, a gene structurally closely related to PDC1 and PDC5. The product of PDC6 does not seem to be required for wild-type pyruvate decarboxylase activity in glucose medium; DELTA-pdc6 mutants have no reduced specific enzyme activity, and the PDC6 deletion did not change the phenotype or the specific enzyme activity of mutants lacking either or both of the other two structural genes. However, in cells grown in ethanol medium the PDC6 deletion caused a reduction of pyruvate decarboxylase activity. Northern (RNA) blot analysis showed that PDC6 is weakly expressed, and expression seemed to be higher during growth in ethanol medium. This behavior remained obscure since pyruvate decarboxylase catalyzes an irreversible reaction. Characterization of all combinations of PDC structural gene deletion mutants, which produce different amounts of pyruvate decarboxylase activity, showed that the enzyme is also needed for normal growth in galactose and ethanol medium and in particular for proper growth initiation of spores germinating on ethanol medium.