Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

Effect of pH on Hydride Transfer by Escherichia coli Dihydrofolate Reductase

Loveridge, Edric Joel and Allemann, Rudolf Konrad 2011. Effect of pH on Hydride Transfer by Escherichia coli Dihydrofolate Reductase. ChemBioChem 12 (8) , pp. 1258-1262. 10.1002/cbic.201000794

Full text not available from this repository.

Abstract

The kinetic isotope effect (KIE) on hydride transfer in the reaction catalysed by dihydrofolate reductase from Escherichia coli (EcDHFR) is known to be temperature dependent at pH 7, but essentially independent of temperature at elevated pH. Here, we show that the transition from the temperature-dependent regime to the temperature-independent regime occurs sharply between pH 7.5 and 8. The activation energy for hydride transfer is independent of pH. The mechanism leading to the change in behaviour of the KIEs is not clear, but probably involves a conformational change in the enzyme brought about by deprotonation of a key residue (or residues) at high pH. The KIE on hydride transfer at low pH suggests that the rate constant for the reaction is not limited by a conformational change to the enzyme under these conditions. The effect of pH on the temperature dependence of the rate constants and KIEs for hydride transfer catalysed by EcDHFR suggests that enzyme motions and conformational changes do not directly influence the chemistry, but that the reaction conditions affect the conformational ensemble of the enzyme prior to reaction and control the reaction though this route.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Cardiff Catalysis Institute (CCI)
Chemistry
Subjects: Q Science > QD Chemistry
Uncontrolled Keywords: dihydrofolate reductase; enzyme catalysis; hydrides; isotope effects; kinetics; pH
Publisher: Wiley-Blackwell
ISSN: 1439-4227
Funders: BBSRC
Last Modified: 05 Jun 2017 02:33
URI: http://orca.cf.ac.uk/id/eprint/14505

Citation Data

Cited 19 times in Google Scholar. View in Google Scholar

Cited 20 times in Scopus. View in Scopus. Powered By Scopus® Data

Cited 16 times in Web of Science. View in Web of Science.

Actions (repository staff only)

Edit Item Edit Item