Activities of phenylalanine and tyrosine aminotransferases in amycolatopsis methanolica mutants

ABSTRACT

Amycolatopsis methanolica mutant GH 141-19 is an auxotrophic strain able to grow on glucose mineral media supplemented with L- phenylalanine plus L-tyrosine mixtures at a doubling time of 2.5 hours, while mutant GH 71 can grow in media supplemented with only L- phenylalanine at doubling time of 3 hours. Mono Q FPLC anion exchange chromatography of strain GH 71 revealed the presence of 2-phenylalanine aminotransferase activity peaks, these overlapped with the 2-tyrosine aminotransferase peaks present. In mutant GH 141-19 only single phenylalanine and overlapping tyrosine aminotransferase peaks were observed indicating that mutant GH 141-19 is deficient in the second aromatic amino acid aminotransferase peak