Kinetic and stereochemical analysis of YwhB, a 4-oxalocrotonate tautomerase homologue in Bacillus subtilis: mechanistic implications for the YwhB- and 4-oxalocrotonate tautomerase-catalyzed reactions.

ABSTRACT: YwhB, a 4-oxalocrotonate tautomerase (4-OT) homologue in Bacillus subtilis, has no known biological role, and the gene has no apparent genomic context. The kinetic and stereochemical properties of YwhB have been examined using available enol and dienol compounds. The kinetic analysis shows that YwhB has a relatively nonspecific 1,3- and 1,5-keto-enol tautomerase activity, with the former activity prevailing. Replacement of Pro-1 or Arg-11 with an alanine significantly reduces or abolishes these activities, implicating both residues as critical ones for the activities. In D2O, ketonization of two monoacid substrates (2-hydroxy-2,4-pentadienoate and phenylenolpyruvate) produces a mixture of stereoisomers {2-keto-3-[2H]-4-pentenoate and 3-[2H]-phenylpyruvate}, where the (3R)-isomers predomina

SUBMITTER: Wang SC 

PROVIDER: S-EPMC2531070 | biostudies-literature | 2007 Oct

REPOSITORIES: biostudies-literature