Site-directed mutagenesis of glutamate 317 of bovine alpha-1,3Galactosyltransferase and its effect on enzyme activity: implications for reaction mechanism.

ABSTRACT: Bovine alpha1,3galactosyltransferase (alpha1,3GalT) transfers galactose from UDP-alpha-galactose to terminal beta-linked galactosyl residues with retention of configuration of the incoming galactose residue. The epitope synthesized has been shown to be critical for xenotransplantation. According to a proposed double-displacement reaction mechanism, glutamate-317 (E317) is thought to be the catalytic nucleophile. The proposed catalytic role of E317 involves an initial nucleophilic attack with inversion of configuration and formation of a covalent sugar-enzyme intermediate between E317 and galactose from the donor substrate, followed by a second nucleophilic attack performed by the acceptor substrate with a second inversion of configuration. To determine whether E317 of alpha1,3GalT is criti

SUBMITTER: Molina P 

PROVIDER: S-EPMC1995746 | biostudies-literature | 2007 Aug

REPOSITORIES: biostudies-literature