Burlini N, Pellegrini R, Facheris P, Tortora P, Guerritore A
Dipartimento di Fisiologia e Biochimica generali, Università di Milano, Italy.
Arch Microbiol. 1993;159(3):220-4. doi: 10.1007/BF00248475.
Preincubation of yeast cells in the presence of benzoate or sorbate at an extracellular pH value of 6.8 elicited a set of metabolic effects on sugar metabolism, which became apparent after the subsequent glucose addition. They can be summarized as follows: a) reduced glucose consumption; b) inhibition of glucose- and fructose-phosphorylating activities; c) suppression of glucose-triggered peak of hexoses monophosphates; d) substantial reduction of glucose-triggered peak of fructose 2,6-bisphosphate; e) block of catabolite inactivation of fructose-1,6-bisphosphatase and phosphoenolpyruvate carboxy-kinase, but not of cytoplasmic malate dehydrogenase. On the whole this pattern resulted in prevention of glucose-induced switch of metabolism from a gluconeogenetic to a glycolytic state. Our data also show that, unlike former assumptions, intracellular acidification is not likely to mediate the bulk of metabolic effects of benzoate and sorbate, since under our working conditions intracellular pH kept close to neutrality.
在细胞外pH值为6.8的条件下，将酵母细胞在苯甲酸盐或山梨酸盐存在的情况下进行预孵育，会对糖代谢产生一系列代谢效应，在随后添加葡萄糖后这些效应变得明显。它们可总结如下：a) 葡萄糖消耗减少；b) 葡萄糖和果糖磷酸化活性受到抑制；c) 葡萄糖引发的己糖单磷酸峰受到抑制；d) 葡萄糖引发的果糖2,6-二磷酸峰大幅降低；e) 果糖-1,6-二磷酸酶和磷酸烯醇式丙酮酸羧激酶的分解代谢失活被阻断，但细胞质苹果酸脱氢酶未受影响。总体而言，这种模式导致防止了葡萄糖诱导的代谢从糖异生状态转变为糖酵解状态。我们的数据还表明，与之前的假设不同，细胞内酸化不太可能介导苯甲酸盐和山梨酸盐的大部分代谢效应，因为在我们的工作条件下，细胞内pH值保持接近中性。
