The route of lysine breakdown in Candida tropicalis

Candila tropicalis</it> was found to contain high levels of the following enzymes after growth in defined medium on <scp>l</scp>-lysine as sole nitrogen source: <scp>l</scp>-lysine N</it>6-acetyltransferase, N6-acetyllysineaminotransferase, and aminotransferase activity for 5-aminovalerate and 4-aminobutyrate. Extracts were also capable of converting 5-acetamidovalerate (and 4-acetamidobutyrate) to acetate. N</it>6-Acetyllysine however, only gave rise to acetate in the presence of 2-oxoglutarate, NAD+ and thiamine pyrophosphate. These activities were undetectable or present in much lower concentrations in cells that had been grown on ammonium sulphate as sole nitrogen source. It is concluded that <scp>l</scp>-lysine is degraded in this organism via N</it>6-acetyllysine, 5-acetamidovalerate and 5-aminovalerate, both nitrogen atoms being removed by transamination.