CSIRO Publishing blank image blank image blank image blank imageBooksblank image blank image blank image blank imageJournalsblank image blank image blank image blank imageAbout Usblank image blank image blank image blank imageShopping Cartblank image blank image blank image You are here: Journals > Functional Plant Biology   
Functional Plant Biology
Journal Banner
  Plant Function & Evolutionary Biology
blank image Search
blank image blank image
blank image
  Advanced Search

Journal Home
About the Journal
Editorial Structure
Online Early
Current Issue
Just Accepted
All Issues
Special Issues
Research Fronts
Evolutionary Reviews
Sample Issue
Call for Papers
For Authors
General Information
Submit Article
Author Instructions
Open Access
Awards and Prizes
For Referees
Referee Guidelines
Review an Article
Annual Referee Index
For Subscribers
Subscription Prices
Customer Service
Print Publication Dates

blue arrow e-Alerts
blank image
Subscribe to our Email Alert or RSS feeds for the latest journal papers.

red arrow Connect with us
blank image
facebook twitter LinkedIn

red arrow PrometheusWiki
blank image
Protocols in ecological and environmental plant physiology


Article << Previous     |     Next >>   Contents Vol 32(4)

Carbon isotope effect predictions for enzymes involved in the primary carbon metabolism of plant leaves

Guillaume Tcherkez A B, Graham D. Farquhar A

A Environmental Biology Group, Research School of Biological Sciences, Institute of Advanced Studies, Australian National University, GPO Box 475, Canberra, ACT 2601, Australia.
B Current address: Laboratoire Structure et Métabolisme des Plantes, Bat. 630, Institut de Biotechnologie des Plantes, Centre Scientifique d’Orsay, Université Paris XI, 91405 Orsay Cedex, France.
Corresponding author. Email: guillaume.tcherkez@ese.u-psud.fr

PDF (289 KB) $25
 Export Citation


Carbon isotope effects of enzymes involved in primary carbon metabolism are key parameters in our understanding of plant metabolism. Nevertheless, some of them are poorly known because of the lack of in vitro experimental data on purified enzymes. Some studies have focused on theoretical predictions of isotope effects. Here we show how quantum chemical calculations can be adapted for calculation of isotope effects for the Rubisco-catalysed carboxylation and oxygenation reactions and the citrate synthase reaction. The intrinsic isotope effect of the carboxylation by Rubisco appears to be much smaller than previously thought, being close to the overall isotope effect of the reaction that is, between 25 and 30 per mil. The same applies to the enzyme citrate synthase, that catalyses the first step of the Krebs cycle, with an isotope effect of around 23 per mil. Combined with the isotope effects of equilibrium reactions calculated with β-factors, the Krebs cycle then has an overall isotope effect that depletes organic acids in 13C.

Keywords: carbon isotopes, carbon metabolism, carboxylation, citrate synthase, enzymes, oxygenation, Rubisco.

Subscriber Login

Legal & Privacy | Contact Us | Help


© CSIRO 1996-2015