title: Structure-activity analysis of base and enzyme-catalyzed 4-hydroxybenzoyl coenzyme A hydrolysis.
abstract: In this study, the second-order rate constant k2 of base-catalyzed hydrolysis and the values of kcat, Km and kcat/Km of wild-type Pseudomonas sp. CBS3 4-hydroxybenzoyl coenzyme A (4-HBA-CoA) thioesterase-catalyzed hydrolysis of 4-HBA-CoA and its para-substituted analogs were measured. For the base-catalyzed hydrolysis, the plot of logk2 vs the sigma value of the para-substituents was linear with a slope (rho) of 1.5. In the case of the enzyme-catalyzed hydrolysis, the kcat/Km values measured for the para-substituted analogs defined substrate specificity. Asp32 was shown to play a key role in substrate recognition, and in particular, in the discrimination between the targeted substrate and other cellular benzoyl-CoA thioesters.
authors.affiliation: Department of Chemistry, University of New Mexico, Albuquerque, NM 87131, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Song
authors.forename: Zhihao
authors.initials: Z
authors.lastname: Zhuang
authors.forename: Debra
authors.initials: D
authors.lastname: Dunaway-Mariano
mesh_terms: D000214:Acyl Coenzyme A / Q000737:chemistry*; D001216:Asparagine / Q000737:chemistry / Q000235:genetics; D002384:Catalysis; D020134:Catalytic Domain; D006860:Hydrogen Bonding; D006868:Hydrolysis; D007700:Kinetics; D008956:Models, Chemical; D015394:Molecular Structure; D016297:Mutagenesis, Site-Directed; D011994:Recombinant Proteins / Q000737:chemistry; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D013869:Thiolester Hydrolases / Q000737:chemistry* / Q000235:genetics
chemical_list: D000214:Acyl Coenzyme A; D011994:Recombinant Proteins; C058482:4-hydroxybenzoyl-coenzyme A; D001216:Asparagine; C092167:4-hydroxybenzoyl-CoA hydrolase; D013869:Thiolester Hydrolases