Pyridoxal 5‘-Phosphate-Dependent α,β-Elimination Reactions: Mechanism of O-Acetylserine Sulfhydrylase
- 3 November 2000
- journal article
- research article
- Published by American Chemical Society (ACS) in Accounts of Chemical Research
- Vol. 34 (1) , 49-59
- https://doi.org/10.1021/ar990169l
Abstract
O-Acetylserine sulfhydrylase catalyzes the replacement of the β-acetoxy group of O-acetyl-l-serine with sulfide to generate l-cysteine. The reaction represents the final step in the biosynthesis of l-cysteine in enteric bacteria and plants. A quinonoid intermediate has not been detected using a variety of kinetic and spectroscopic probes for the wild-type or mutant enzymes, ruling out an E1 mechanism. The structure of the external Schiff base intermediate indicates an anti elimination. O-Acetylserine sulfhydrylase is the only known pyridoxal 5‘-phosphate-dependent enzyme that catalyzes a β-elimination reaction to have an anti E2 mechanism.Keywords
This publication has 21 references indexed in Scilit:
- Ligand binding induces a large conformational change in O-acetylserine sulfhydrylase from Salmonella typhimuriumJournal of Molecular Biology, 1999
- A Change in the Internal Aldimine Lysine (K42) in O-Acetylserine Sulfhydrylase to Alanine Indicates Its Importance in Transimination and as a General Base CatalystBiochemistry, 1996
- Formation of the α-Aminoacrylate Intermediate Limits the Overall Reaction Catalyzed by O-Acetylserine SulfhydrylaseBiochemistry, 1996
- Identification and Spectral Characterization of the External Aldimine of the O-Acetylserine Sulfhydrylase ReactionBiochemistry, 1995
- Understanding the rates of certain enzyme-catalyzed reactions: Proton abstraction from carbon acids, acyl transfer reactions, and displacement reactions of phosphodiestersBiochemistry, 1993
- Mechanism of the reaction catalyzed by mandelate racemase. 2. Crystal structure of mandelate racemase at 2.5-.ANG. resolution: identification of the active site and possible catalytic residuesBiochemistry, 1991
- Detection and identification of intermediates in the reaction of L-serine with Escherichia coli tryptophan synthase via rapid-scanning ultraviolet-visible spectroscopyBiochemistry, 1985
- Stereochemistry and mechanism of reactions catalyzed by tryptophanase and tryptophan synthetaseJournal of the American Chemical Society, 1976
- Stereochemistry of .beta.-replacement reactions catalyzed by tyrosine phenol-lyaseJournal of the American Chemical Society, 1975
- Heterocyclic Compounds. VI. Reduction of 3-(3,4-Methylenedioxyphenyl)-4-nitro-1-phenyl-1-butanone1Journal of the American Chemical Society, 1958