Plant Physiol. Journal of Pharmacology and Experimental Therapeutics
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Plant Physiology 75:983-987 (1984)
© 1984 American Society of Plant Biologists

This Article
Right arrow Full Text (PDF)
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 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
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Iglesias, A. A.
Right arrow Articles by Andreo, C. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Iglesias, A. A.
Right arrow Articles by Andreo, C. S.
Agricola
Right arrow Articles by Iglesias, A. A.
Right arrow Articles by Andreo, C. S.
Articles

On the Molecular Mechanism of Maize Phosphoenolpyruvate Carboxylase Activation by Thiol Compounds 1

Alberto A. Iglesias2 and Carlos S. Andreo2

Centro de Estudios Fotosintéticos y Bioquímicos, Suipacha 531, 2000 Rosario, Argentina (Consejo Nacional de Investigaciones Científicas y Técnicas, F. M. Lillo y U. N. de Rosario)

Incubation of purified phosphoenolpyruvate carboxylase from Zea mays L. leaves with dithiothreitol resulted in an almost 2-fold increase in the enzymic activity. The activated enzyme showed the same affinity for its substrates and the same sensitivity with respect to malate and oxalacetate inhibition. The activation induced by dithiothreitol was reversed by diamide, an oxidant of vicinal dithiols, suggesting that the redox state of disulfide bonds of the enzyme may be important in the expression of the maximal catalytic activity.

Titration of thiol groups before and after activation of maize phosphoenolpyruvate carboxylase by dithiothreitol shows an increase of the accessible groups from 8 to 12 suggesting that the reduction of two disulfide bonds accompanied the activation. The thiols exposed by the treatment with dithiothreitol were available to reagents in nondenatured enzyme and two of them were reoxidized to a disulfide bond by diamide. It is concluded that the mechanism of phosphoenolpyruvate carboxylase activation by dithiothreitol involves the net reduction of two disulfide bonds in the enzyme.

2 C. S. A. is a Member of the Investigator Career of the Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET, Argentina, and A. A. I. is a Fellow of the same institution.

1 Supported by grants from Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET, Argentina.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
ASPB Publications PLANT PHYSIOLOGY THE PLANT CELL
Copyright © 1984 by the American Society of Plant Biologists