title: Replacement of tyrosine 181 by phenylalanine in gentisate 1,2-dioxygenase I from Pseudomonas alcaligenes NCIMB 9867 enhances catalytic activities.
abstract: xlnE, encoding gentisate 1,2-dioxygenase (EC 1.13.11.4), from Pseudomonas alcaligenes (P25X) was mutagenized by site-directed mutagenesis. The mutant enzyme, Y181F, demonstrated 4-, 3-, 6-, and 16-fold increases in relative activity towards gentisate and 3-fluoro-, 4-methyl-, and 3-methylgentisate, respectively. The specific mutation conferred a 13-fold higher catalytic efficiency (k(cat)/Km) on Y181F towards 3-methylgentisate than that of the wild-type enzyme.
authors.affiliation: Programme in Environmental Microbiology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117597.
authors.forename: Chew Ling
authors.initials: CL
authors.lastname: Tan
authors.forename: Chew Chieng
authors.initials: CC
authors.lastname: Yeo
authors.forename: Hoon Eng
authors.initials: HE
authors.lastname: Khoo
authors.forename: Chit Laa
authors.initials: CL
authors.lastname: Poh
mesh_terms: D019943:Amino Acid Substitution; D002384:Catalysis; D049308:Dioxygenases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D005841:Gentisates / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D020125:Mutation, Missense; D044202:Pseudomonas alcaligenes / Q000201:enzymology* / Q000235:genetics; D013379:Substrate Specificity
chemical_list: D005841:Gentisates; D049308:Dioxygenases; C026247:gentisate 1,2-dioxygenase