Maitra P K, Lobo Z
Mol Gen Genet. 1977 Apr 29;152(3):193-200. doi: 10.1007/BF00268817.
Mutants of Saccharomyces cerevisiae lacking pyruvate kinase (EC 2.7.1.40) are described. These have less than 0.5% of the pyruvate kinase activity of the wild type. All the other glycolytic enzymes are present in normal amounts in these mutants. The mutation is recessive and segregates in diploids as a single gene. Five alleles examined fail to complement one another. Tetrad analysis and mitotic recombination data place the mutation on the left arm of chromosome I distal to cys 1. The majority of single-step spontaneous revertants on glucose regain the enzyme activity fully and this activity appears, by a number of criteria, to be due to the same enzyme present in the wild type. Some of these revertants become nuclear petites. The mutants do neither grow on nor ferment sugars but do grow on ethyl alcohol or pyruvate. Glucose addition to cultures growing on alcohol arrests growth until glucose is exhausted. The steady state rate of glucose utilization is slower than in the wild type. This is associated with the accumulation of as much as 5 micronmoles P-enolpyruvate per g wet weight of cells and proportional amounts of 2-P-glyceric and 3-P glyceric acids. The mutation is believed to involve some regulatory element in the synthesis of pyruvate kinase.
本文描述了缺乏丙酮酸激酶（EC 2.7.1.40）的酿酒酵母突变体。这些突变体的丙酮酸激酶活性不到野生型的0.5%。在这些突变体中，所有其他糖酵解酶的含量均正常。该突变是隐性的，在二倍体中作为单个基因分离。所检测的五个等位基因不能相互互补。四分体分析和有丝分裂重组数据将该突变定位在第一条染色体左臂上，位于半胱氨酸1的远端。大多数在葡萄糖上的单步自发回复突变体完全恢复了酶活性，并且根据一些标准，这种活性似乎是由于野生型中存在的同一种酶所致。其中一些回复突变体变成了核小菌落。这些突变体既不能在糖上生长也不能发酵糖，但能在乙醇或丙酮酸上生长。向在乙醇上生长的培养物中添加葡萄糖会使生长停止，直到葡萄糖耗尽。葡萄糖的稳态利用率比野生型慢。这与每克细胞湿重积累多达5微摩尔的磷酸烯醇丙酮酸以及相应量的2-磷酸甘油酸和3-磷酸甘油酸有关。据信该突变涉及丙酮酸激酶合成中的一些调节元件。
