Mitochondrial aldehyde dehydrogenase; K+ dependent enzyme that can use either NADP+ or NAD+ as cofactor; required for growth on ethanol and for conversion of acetaldehyde to acetate; can substitute for cytosolic NADP-dependent aldehyde dehydrogenase when directed to the cytosol; influences lipid metabolism; polymerizes into filaments in meiotic cells; phosphorylated; expression is glucose repressed; human homolog ALDH2 can complement a yeast ald4 mutant