Participation of acetaldehyde dehydrogenases in ethanol and pyruvate metabolism of the yeast Saccharomyces cerevisiae
Participation of acetaldehyde dehydrogenases in ethanol and pyruvate metabolism of the yeast Saccharomyces cerevisiae
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DOI：
10.1046/j.1432-1327.2001.02418.x
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发表时间：
2001-10-01
期刊：
影响因子：
--
通讯作者：
Guérin, B
中科院分区：
文献类型：
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作者：
Boubekeur, S;Camougrand, N;Guérin, B
这项工作的目的是阐明乙醛脱氢酶在酿酒酵母呼吸底物生长过程中代谢中的作用。到目前为止，对于编码线粒体乙醛脱氢酶的基因 ALD4 中缺失的突变体在乙醇中生长的能力尚未达成一致。因此，我们在两个亲本菌株（YPH499 和 W303-1a）中构建了突变体。从这两个亲本菌株获得的突变体的生长特性出现了一些差异。对于这些实验，我们使用乙醇、丙酮酸盐或乳酸盐作为底物。线粒体可以利用 ATP 合成耦合途径将乳酸氧化为丙酮酸。来自YPH499菌株的ald4 Delta突变体不能在乙醇中生长，但来自W303-1a的ald4 Delta突变体可以生长。拉紧。 ALD4 和 PDA1（编码丙酮酸脱氢酶亚基 E1 α）的共同破坏阻止了两种菌株在丙酮酸上的生长，但仅在源自 YPH499 菌株的双突变体中阻止了在乳酸上的生长，表明突变效应是菌株依赖性的。为了了解这些差异，我们测量了这些不同菌株的酶含量。我们发现：（a）与W303-1a菌株相比，YPH499中胞质乙醛脱氢酶的活性相对较低； (b)通过在培养基中添加乙酸盐或通过将携带编码胞质乙醛脱氢酶的ALD6基因的多拷贝质粒引入该突变体，可以恢复源自YPH499的突变体的生长。因此，来自YPH499菌株的突变体生长缺乏似乎与乙醛氧化活性低有关。因此，当在乙醇上培养时，只有当胞质酶的活性足够时，胞质乙醛脱氢酶才能部分补偿线粒体乙醛脱氢酶的缺乏。然而，当在丙酮酸上培养且缺乏丙酮酸脱氢酶时，胞质乙醛脱氢酶无法补偿线粒体酶的缺乏，因为线粒体形式通过氧化磷酸化产生线粒体内NADH并因此产生ATP。
This work was undertaken to clarify the role of acetaldehyde dehydrogenases in Saccharomyces cerevisiae metabolism during growth on respiratory substrates. Until now, there has been little agreement concerning the ability of mutants deleted in gene ALD4, encoding mitochondrial acetaldehyde dehydrogenase, to grow on ethanol. Therefore we constructed mutants in two parental strains (YPH499 and W303-1a). Some differences appeared in the growth characteristics of mutants obtained from these two parental strains. For these experiments we used ethanol, pyruvate or lactate as substrates. Mitochondria can oxidize lactate into pyruvate using an ATP synthesis-coupled pathway. The ald4 Delta ,A mutant derived from the YPH499 strain failed to grow on ethanol, but growth was possible for the ald4 Delta mutant derived from the W303-1a. strain. The co-disruption of ALD4 and PDA1 (encoding subunit E1 alpha. of pyruvate dehydrogenase) prevented the growth on pyruvate for both strains but prevented growth on lactate only in the double mutant derived from the YPH499 strain, indicating that the mutation effects are strain-dependent. To understand these differences, we measured the enzyme content of these different strains. We found the following: (a) the activity of cytosolic acetaldehyde dehydrogenase in YPH499 was relatively low compared to the W303-1a strain; (b) it was possible to restore the growth of the mutant derived from YPH499 either by addition of acetate in the media or by introduction into this mutant of a multicopy plasmid carrying the ALD6 gene encoding cytosolic acetaldehyde dehydrogenase. Therefore, the lack of growth of the mutant derived from the YPH499 strain seemed to be related to the low activity of acetaldehyde oxidation. Therefore, when cultured on ethanol, the cytosolic acetaldehyde dehydrogenase can partially compensate for the lack of mitochondrial acetaldehyde dehydrogenase only when the activity of the cytosolic enzyme is sufficient. However, when cultured on pyruvate and in the absence of pyruvate dehydrogenase, the cytosolic acetaldehyde dehydrogenase cannot compensate for the lack of the mitochondrial enzyme because the mitochondrial form produces intramitochondrial NADH and consequently ATP through oxidative phosphorylation.