Distribution of three lysine‐catabolizing enzymes in various yeast species

Abstract

28 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-acetyltrdnSferdSe, L-lysine e-aminotransferase, L-lysine Edehydrogenase, 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 dehydrogenage could be detected. The enzyme formation could be enhanced in cells grown in the presence of L-lysine as sole carbon and/or as sole nitrogen source.Both the biosynthesis and the catabolism of L-lysine show considerable variation from one life form to another. No fewer than 8 distinct catabolic routes for this amino acid have been proposed for animals, fungi and bacteria. The initial steps are the following reactions :

Purification and characterization of an inducible L‐lysine: 2‐oxoglutarate 6‐aminotransferase from Candida utilis

“…The high derepression of the aminotransferase activity from yeast cells grown in lysine-containing media indicates that the enzyme plays an important role in the catabolism of L-lysine in C. urilis. A significant derepression by lysine was also observed for LAT from other yeasts investigated (HAMMER et al 1991, KIKZEL P I c i / . 1983.…”

Candida maltosa

“…The first two enzymes of this pathway, the novel acetyl-CoA:L-lysine N-acetyltransferase (EC 2.3.1, Schmidt et al 1988;Hammer et al 1991) and the W-acetyl-L-lysine:2-oxoglutarate aminotransferase (AcL-AT, Schmidt and Bode 1992) were first detected in yeast in C. maltosa. The two enzymes were characterized after partial and total purification, respectively.…”

“…The two enzymes were characterized after partial and total purification, respectively. Further degradation of the 2-keto-acetamidocaproate and 5-aminovalerate to glutarate has been described in this yeast as in Y. lipolytica, whereas P. guilliermondii and C. albicans use the oxidative transamination as the first step (Hammer et al 1991).…”

Regulation of Amino Acid Transport in Saccharomyces cerevisiae

“…Not only do amino acids act as the building blocks of proteins, but S. cerevisiae can also use most proteinogenic amino acids, as well as citrulline, ornithine, and GABA, as a sole nitrogen source (14). The exceptions are cysteine, histidine, and lysine, although other yeasts, including some Saccharomyces strains, are able to use lysine as a sole N source (15)(16)(17)(18). The catabolism of most amino acids also provides a source of carbon, except for those that feed into the Ehrlich pathway (19) numerous metabolic pathways, including the synthesis of NAD ϩ , folate, glutathione, nucleotides, polyamines, and phospholipids.…”