Abstract28 yeast strains comprising a number of genera and species have been studied with respect to their ability to use l‐lysine as carbon or nitrogen source. Based on the utilization of this amino acid we could separate the yeasts into 3 groups. Enzymatic investigations demonstrate that yeasts can degrade l‐lysine by two distinct pathways. The first step of both ways was investigated and it was demonstrated that 3 enzymes, acetyl‐CoA: l‐lysine N‐acetyltransferase, l‐lysine α‐aminotransferase, l‐lysine α‐dehydrogenase, are able to catalyze the initial reaction. In 9 yeast strains the acetyltransferase was found. In 21 strains the aminotransferase and in 2 species the dehydrogenase could be detected. The enzyme formation could be enhanced in cells grown in the presence of l‐lysine as sole carbon and/or as