Product-assisted catalysis as the basis of the reaction specificity of threonine synthase.

ABSTRACT: Threonine synthase (TS), which is a pyridoxal 5'-phosphate (PLP)-dependent enzyme, catalyzes the elimination of the γ-phosphate group from O-phospho-L-homoserine (OPHS) and the subsequent addition of water at Cβ to form L-threonine. The catalytic course of TS is the most complex among the PLP enzymes, and it is an intriguing problem how the elementary steps are controlled in TS to carry out selective reactions. When L-vinylglycine was added to Thermus thermophilus HB8 TS in the presence of phosphate, L-threonine was formed with k(cat) and reaction specificity comparable with those when OPHS was used as the substrate. However, in the absence of phosphate or when sulfate was used in place of phosphate, only the side reaction product, α-ketobutyrate, was formed. Global analysis of the spectra

SUBMITTER: Murakawa T 

PROVIDER: S-EPMC3024773 | biostudies-literature | 2011 Jan

REPOSITORIES: biostudies-literature