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Your search keyword '"Kui Chan"' showing total 4 results
Start Over Author "Kui Chan" Journal journal of the american chemical society
4 results on '"Kui Chan"'

1. Product deuterium isotope effects for orotidine 5'-monophosphate decarboxylase: effect of changing substrate and enzyme structure on the partitioning of the vinyl carbanion reaction intermediate

Author

Toth, Krisztina, Amyes, Tina L., Wood, Bryant M., Kui Chan, Gerlt, John A., and Richard, John P.

Subjects
Deuterium -- Chemical properties, Gene mutations -- Analysis, Pyrimidine nucleotides -- Structure, Pyrimidine nucleotides -- Chemical properties, Brewer's yeast -- Physiological aspects, Brewer's yeast -- Genetic aspects, Uridine -- Chemical properties, Chemistry
Abstract

A product deuterium isotope effect (PIE) of 1.0 is determined as the ratio of the yields of [6-[super 1]H]-uridine 5'-monophosphate and [6-[supe 2]H]-uridine 5'-monophosphate from the decarboxylation of orotidine 5'-monophosphate (OMPDC) from Saccharomyces cerevisiae, Methanothermobacter thermautotrophicus, and Escherichia coli. Mutations on the active-site residues of OMPDC from S. cerevisiae have no effect on the PIE on OMPDC-catalyzed decarboxylation of OMP or decarboxylation of 5-FOMP:R235A, Y217A, Q215A, S124A, and S154A/Q215A.

Published
2010

2. Product deuterium isotope effect for orotidine 5'-monophosphate decarboxylase: evidence for the existence of a short-lived carbanion intermediate

Author

Toth, Krisztina, Amyes, Tina L., Wood, Bryant M., Kui Chan, Gerlt, John A., and Richard, John P.

Subjects
Deuterium -- Structure, Deuterium -- Chemical properties, Deuterium -- Spectra, Nuclear magnetic resonance spectroscopy -- Analysis, Phosphates -- Structure, Phosphates -- Chemical properties, Phosphates -- Spectra, Chemistry
Abstract

The decarboxylation of orotidine 5'-monophosphate (OMP) catalyzed by orotidine 5'-monophosphate decarboxylase in a solvent of [H.sub.2]O/[D.sub.2]O is reported. Equal amount of [6-[super 1]H]-uridine 5'-monophosphate and [6-[super 2]H]-uridine 5'-monophosphate decarboxylation are yielded.

Published
2007

3. Formation and stability of a vinyl carbanion at the active site of orotidine 5'-monophosphate decarboxylase: p[K.sub.a] of the C-6 proton of enzyme-bound UMP

Author

Amyes, Tina L., Wood, Bryant M., Kui Chan, Gerlt, John A., and Richard, John P.

Subjects
Nucleosides -- Research, Nucleosides -- Chemical properties, Decarboxylases -- Research, Decarboxylases -- Chemical properties, Transition state (Chemistry) -- Observations, Chemistry
Abstract

Orotidine 5'-monophosphate decarboxylase (OMPDC) has catalyzed exchange of the C-6 proton of uridine 5'-monophosphate (UMP) for deuterium from solvent in [D.sub.2]O. The studies have shown that OMPDC has provided stabilization of the late carbanion-like transition state for the decarboxylation of OMP and that this transition state stabilization has constituted a large fraction of enzymatic rate acceleration.

Published
2008

4. Formation and Stability of a Vinyl Carbanion at the Active Site of Orotidine 5'-Monophosphate Decarboxylase: pKa of the C-6 Proton of Enzyme-Bound UMP.

Author

Amyes, Tina L., Wood, Bryant M., Kui Chan, Gerit, John A., and Richard, John P.

Subjects
*DECARBOXYLASES, *LYASES, *BINDING sites, *CHEMICAL research, *PHYSICAL & theoretical chemistry
Abstract

The article focuses on the study about the formation and stability of a vinyl carbanion at the active site of orotidine 5'-monophosphate decarboxylase (OMPDC). Researchers conlcude that further experimental studies directed at elucidating the origin of the transition state stabilization of OMPDC will provide insight into its so far unexplained extraordinary catalytic power.

Published
2008
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