Monofunctional chorismate mutase from Bacillus subtilis: kinetic and 13C NMR studies on the interactions of the enzyme with its ligands

Gray, J. V., Eren, D. and Knowles, J. R. (1990) Monofunctional chorismate mutase from Bacillus subtilis: kinetic and 13C NMR studies on the interactions of the enzyme with its ligands. Biochemistry, 29(37), pp. 8872-8878. (doi:10.1021/bi00489a051) (PMID:2125470)

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Abstract

The interaction of the monofunctional chorismate mutase from Bacillus subtilis with chorismate and prephenate has been studied kinetically and by NMR spectroscopy with 13C specifically labeled substrates. Prephenate dominates the population of enzyme-bound species, and the "off" rate constant (approximately 60 s-1) obtained from line-broadening experiments is close to the value of kcat for chorismate (50 s-1) determined kinetically. The calculated "on" rate constant for prephenate (8 x 10(5) M-1 s-1) is similar to the value of kcat/Km for chorismate (5 x 10(5) M-1 s-1). The kinetic parameters of the Bacillus mutase are remarkably insensitive to pH over a wide range and display no solvent isotope effect. These results suggest that the enzyme-catalyzed reaction may be encounter controlled (slowed from the diffusion limit by some feature of the enzyme's active site) and that kcat for chorismate is determined by the product off rate. There is now no evidence to suggest that the skeletal rearrangement on the enzyme surface occurs by a pathway other than a pericyclic process.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Gray, Dr Joseph
Authors: Gray, J. V., Eren, D., and Knowles, J. R.
Subjects:Q Science > QH Natural history > QH345 Biochemistry
College/School:College of Medical Veterinary and Life Sciences > School of Life Sciences
Journal Name:Biochemistry
Publisher:American Chemical Society
ISSN:0006-2960
ISSN (Online):1520-4995

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