Goldson Barnaby, Andrea; Scaman, C
Author Affiliation, Ana.
Purification and characterization of phenylalanine ammonia lyase from Trichosporon cutaneum
Date of Publication
Article ID 670702
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. MichaelisMenten kinetics (Phe, ???? 5.0 ± 1.1 mM) and positive allostery (Tyr, ???? 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.....