DIFFERENTIAL SENSITIVITIES TO GLUCOSE AND GALACTOSE REPRESSION OF GLUCONEOGENIC AND RESPIRATORY ENZYMES FROM SACCHAROMYCES-CEREVISIAE
DIFFERENTIAL SENSITIVITIES TO GLUCOSE AND GALACTOSE REPRESSION OF GLUCONEOGENIC AND RESPIRATORY ENZYMES FROM SACCHAROMYCES-CEREVISIAE
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DOI：
10.1007/bf00411238
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发表时间：
1985-01-01
影响因子：
2.8
通讯作者：
MORENO, F
中科院分区：
文献类型：
--
作者：
HERRERO, P;FERNANDEZ, R;MORENO, F
恒化器中乙醇的存在可诱导异柠檬酸裂解酶的合成，其比活力可达200 mU·cNTDot。Mg-1处于这种诱导状态。在葡萄糖受限的低谷细胞中，20微米。Mg-1，在抑制条件下未检测到异柠檬酸裂解酶活性。在恒温培养条件下，研究了胞质苹果酸脱氢酶、果糖1，6-二磷酸酶和异柠檬酸裂解酶以及线粒体酶NADH脱氢酶和琥珀酸细胞色素C氧化酶对葡萄糖和半乳糖抑制的敏感性。我们的结果表明，半乳糖作为一种抑制物不如葡萄糖有效。苹果酸脱氢酶完全被葡萄糖灭活，而半乳糖使比活力降低78%。果糖1，6-二磷酸酶和异柠檬酸裂解酶被两种糖完全灭活，但失活速度不同。葡萄糖使线粒体酶的比活性降低了85%，而半乳糖只降低了67%。
The synthesis of isocitrate lyase was induced by the presence of ethanol in the chemostat reaching a specific activity of 200 mU .cntdot. mg-1 at this induced state. In glucose-limited, depressed cells, 20 mU .cntdot. mg-1 were detected and under repressed conditions isocitrate lyase activity was not detected. The sensitivity of gluconeogenic enzymes: cytoplasmic malate dehydrogenase; fructose 1,6-bisphosphatase and isocitrate lyase as well as the mitochondrial enzymes NADH dehydrogenase and succinate cytochrome c oxidase to glucose and galactose repression were studied in chemostat cultures. Our results show that galactose was less effective as a repressor than glucose. Malate dehydrogenase was completely inactivated by glucose, whereas galactose ony produced a 78% decrease of specific activity. Fructose 1,6-bisphosphatase and isocitrate lyase were completely inactivated by both sugars but at different rate. Glucose produced an 85% decrease of specific activity of the mitochondrial enzymes whereas galactose only decrease an 67%.