Denis C L, Ferguson J, Young E T
J Biol Chem. 1983 Jan 25;258(2):1165-71.
The classical, fermentative alcohol dehydrogenase from Saccharomyces cerevisiae, which previously was thought to be constitutive, has been shown to be repressed by growth on nonfermentative carbon sources. The rate of alcohol dehydrogenase I protein synthesis declined 6-fold within 3 to 4 after yeast were transferred from medium containing glucose to medium containing ethanol, and it declined 10-fold after glucose became depleted from the medium during diauxic growth. The decreased rate of alcohol dehydrogenase I protein synthesis was shown not to be the result of an increased rate of degradation of the alcohol dehydrogenase I protein. The decline in alcohol dehydrogenase I protein synthesis was correlated with a 6- to 10-fold decrease in the amount of functional alcohol dehydrogenase I mRNA within 3 to 4 h after transfer from glucose-containing medium to medium containing ethanol. A similar decrease in alcohol dehydrogenase I functional mRNA occurred when cells were depleted of glucose by diauxic growth. Total alcohol dehydrogenase I mRNA, as detected by hybridization to the cloned ADC1 gene, was found in the same relative abundance as the amount of translatable alcohol dehydrogenase I mRNA during the different growth conditions. These results suggest that the alcohol dehydrogenase I protein is transcriptionally regulated.
来自酿酒酵母的经典发酵型乙醇脱氢酶，以前被认为是组成型的，但现已表明在以非发酵性碳源生长时会受到抑制。当酵母从含葡萄糖的培养基转移到含乙醇的培养基后，乙醇脱氢酶I蛋白质合成速率在3至4小时内下降了6倍，而在双相生长期间培养基中的葡萄糖耗尽后，其合成速率下降了10倍。乙醇脱氢酶I蛋白质合成速率的降低并非乙醇脱氢酶I蛋白质降解速率增加所致。从含葡萄糖的培养基转移到含乙醇的培养基后3至4小时内，乙醇脱氢酶I蛋白质合成的下降与功能性乙醇脱氢酶I mRNA量下降6至10倍相关。当细胞通过双相生长耗尽葡萄糖时，乙醇脱氢酶I功能性mRNA也出现类似下降。通过与克隆的ADC1基因杂交检测到的总乙醇脱氢酶I mRNA，在不同生长条件下与可翻译的乙醇脱氢酶I mRNA量具有相同的相对丰度。这些结果表明乙醇脱氢酶I蛋白质受到转录调控。
