Open AccessParticipation of acetaldehyde dehydrogenases in ethanol and pyruvate metabolism of the yeast Saccharomyces cerevisiae
Author(s) -
Boubekeur Samira,
Camougrand Nadine,
Bunoust Odile,
Rigoulet Michel,
Guérin Bernard
Publication year - 2001
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1033.2001.02418.x
Subject(s) - acetaldehyde , alcohol dehydrogenase , mutant , pyruvate dehydrogenase complex , biochemistry , saccharomyces cerevisiae , branched chain alpha keto acid dehydrogenase complex , yeast , lactate dehydrogenase , strain (injury) , biology , pyruvate decarboxylase , dehydrogenase , pyruvate dehydrogenase kinase , respiratory chain , ethanol metabolism , zymomonas mobilis , ethanol , enzyme , gene , ethanol fuel , anatomy
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 ald4Δ mutant derived from the YPH499 strain failed to grow on ethanol, but growth was possible for the ald4Δ mutant derived from the W303‐1a strain. The co‐disruption of ALD4 and PDA1 (encoding subunit E1α 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.