Escherichia coli chorismate synthase: a deuterium kinetic-isotope effect under single-turnover and steady-state conditions shows that a flavin intermediate forms before the C-(6proR)-H bond is cleaved.
- Abstract:
- We report the observation of a deuterium kinetic isotope effect for the conversion of 5-enolpyruvylshikimate-3-phosphate into chorismate (6proR2HV = 1.13 +/- 0.03) using recombinant chorismate synthase from Escherichia coli. Similar isotope effects were observed for the decay of a spectroscopically characterized flavin intermediate (6proR2Hk = 1.17 +/- 0.04) during single-turnover experiments. The main rate-limiting steps and C-(6proR)-H bond breaking are therefore distinct and both must occur after the formation of the flavin intermediate and either before or concomitant with its decay.
- Authors:
- S Bornemann, S Balasubramanian, JR Coggins, C Abell, DJ Lowe, RN Thorneley
- Journal:
- Biochem J
- Citation info:
- 305 ( Pt 3)(Pt 3):707-710
- Publication date:
- 1st Feb 1995
- Full text
- DOI