Substrate Form of D-Fructose 1,6-Bisphosphate Utilized by Fructose 1,6-Bisphosphatase

William A. Frey, Richard Fishbein, Margaret M. de Maine, Stephen J. Benkovic

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Abstract

Rapid quench kinetic experiments on fructose 1,6-bisphosphatase demonstrate a stereospecificity for the α anomer of fructose 1,6-bisphosphate relative to the β configuration. The β anomer is only utilized after mutarotation to the α form in a process that is not enzyme catalyzed. Studies employing analogues of the acyclic keto configuration indicate that the keto form is utilized at a rate less than 5% that of the α anomer, a finding also confirmed by computer simulation of the rapid quench data. Chemical trapping experiments of the keto analogue, xylulose 1,5-bisphosphate, and the normal substrate suggest that interconversion of the acyclic and anomeric configurations is retarded by their binding to the enzyme. A hypothesis is advanced attributing substrate inhibition of fructose 1,6-bisphosphatase to possible binding of the keto species.

Original languageEnglish (US)
Pages (from-to)2479-2484
Number of pages6
JournalBiochemistry
Volume16
Issue number11
DOIs
Publication statusPublished - May 1 1977

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All Science Journal Classification (ASJC) codes

  • Biochemistry

Cite this

Frey, W. A., Fishbein, R., de Maine, M. M., & Benkovic, S. J. (1977). Substrate Form of D-Fructose 1,6-Bisphosphate Utilized by Fructose 1,6-Bisphosphatase. Biochemistry, 16(11), 2479-2484. https://doi.org/10.1021/bi00630a025