THE ALD6 GENE OF SACCHAROMYCES-CEREVISIAE ENCODES A CYTOSOLIC, MG2-ACTIVATED ACETALDEHYDE DEHYDROGENASE()

The deduced translation product of an open reading frame on the left a rm of chromosome XVI of Saccharomyces cerevisiae, with the systematic name of YPL061w, is 500 amino acids in length and shares significant h omology with aldehyde dehydrogenases. Amino acids 2 to 16 of the prote in encoded by YPL061w were found to be identical to the N-terminal 15 amino acids of the purified cytosolic, Mg2+-activated acetaldehyde deh ydrogenase (ACDH) of S. cerevisiae. This enzyme is thought to be invol ved in the production of acetate from which cytosolic acetyl-CoA is th en synthesized. Deletion of YPL061w was detrimental to the growth of h aploid strains of yeast; an analysis of one deletion mutant revealed a maximum specific growth rate (in complex medium containing glucose) o f one-third of that displayed by the wild-type strain. Mutants deleted in YPL061w were also unable to use ethanol as a carbon source. As exp ected, the cytosolic, Mg2+-activated ACDH activity had been lost from the mutants, although the mitochondrial, K+-activated ACDH was readily detected. YPL061w has been registered with the name of ALD6 in the Sa ccharomyces Genome Database and the nucleotide sequence submitted to G enBank as part of accession number U39205. (C) 1997 John Wiley & Sons, Ltd.