Purification and Characterization of Phenylalanine Ammonia Lyase from Trichosporon cutaneum.

ABSTRACT: Trichosporon cutaneum phenylalanine ammonia lyase was selected as a model to investigate the dual substrate activity of this family of enzymes. Sequencing of the PAL gene identified an extensive intron region at the N-terminus. Five amino acid residues differing from a prior report were identified. Highest Phe?:?Tyr activities (1.6? ± 0.3?:?0.4 ± 0.1? ? mol/h?g wet weight) were induced by Tyr. The enzyme has a temperature optimum of 32°C and a pH optimum of 8-8.5 and shows no metal cofactor dependence. Michaelis-Menten kinetics (Phe, K m ??5.0? ± ?1.1?mM) and positive allostery (Tyr, K'??2.4? ± ?0.6?mM, Hill coefficient 1.9 ± 0.5) were observed. Anion exchange chromatography gave a purification fold of 50 with 20% yield. The His-Gln motif (substrate selectivity switch region) indicates the enzyme's ability to act on both substrates.

SUBMITTER: Goldson-Barnaby A 

PROVIDER: S-EPMC3789393 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature