Plant Physiol.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

First published online April 15, 2009; 10.1104/pp.109.136929

Plant Physiology 150:596-605 (2009)
© 2009 American Society of Plant Biologists

This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
150/2/596    most recent
pp.109.136929v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via CrossRef
Google Scholar
Right arrow Articles by Leferink, N. G.H.
Right arrow Articles by van Berkel, W. J.H.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Leferink, N. G.H.
Right arrow Articles by van Berkel, W. J.H.
Agricola
Right arrow Articles by Leferink, N. G.H.
Right arrow Articles by van Berkel, W. J.H.
BIOCHEMICAL PROCESSES AND MACROMOLECULAR STRUCTURES

Galactonolactone Dehydrogenase Requires a Redox-Sensitive Thiol for Optimal Production of Vitamin C1

Nicole G.H. Leferink, Esther van Duijn, Arjan Barendregt, Albert J.R. Heck and Willem J.H. van Berkel*

Laboratory of Biochemistry, Wageningen University, 6703 HA Wageningen, The Netherlands (N.G.H.L., W.J.H.v.B.); Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CA Utrecht, The Netherlands (E.v.D., A.B., A.J.R.H.); and Netherlands Proteomics Centre, 3584 CA Utrecht, The Netherlands (E.v.D., A.B., A.J.R.H.)

The mitochondrial flavoenzyme L-galactono-{gamma}-lactone dehydrogenase (GALDH) catalyzes the ultimate step of vitamin C biosynthesis in plants. We found that recombinant GALDH from Arabidopsis (Arabidopsis thaliana) is inactivated by hydrogen peroxide due to selective oxidation of cysteine (Cys)-340, located in the cap domain. Electrospray ionization mass spectrometry revealed that the partial reversible oxidative modification of Cys-340 involves the sequential formation of sulfenic, sulfinic, and sulfonic acid states. S-Glutathionylation of the sulfenic acid switches off GALDH activity and protects the enzyme against oxidative damage in vitro. C340A and C340S GALDH variants are insensitive toward thiol oxidation, but exhibit a poor affinity for L-galactono-1,4-lactone. Cys-340 is buried beneath the protein surface and its estimated pKa of 6.5 suggests the involvement of the thiolate anion in substrate recognition. The indispensability of a redox-sensitive thiol provides a rationale why GALDH was designed as a dehydrogenase and not, like related aldonolactone oxidoreductases, as an oxidase.

1 This work was supported by a grant from the Carbohydrate Research Centre Wageningen and the Netherlands Proteomics Centre, which is part of the Netherlands Genomics Initiative.

The author responsible for the distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Willem J.H. van Berkel (willem.vanberkel{at}wur.nl).

www.plantphysiol.org/cgi/doi/10.1104/pp.109.136929

* Corresponding author; e-mail willem.vanberkel{at}wur.nl.

Received February 10, 2009; accepted April 9, 2009; published April 15, 2009.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
ASPB Publications PLANT PHYSIOLOGY® THE PLANT CELL
Copyright © 2009 by the American Society of Plant Biologists