HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 278, Issue 24, 21550-21558, June 13, 2003

This Article Full Text Full Text (PDF) All Versions of this Article: 278/24/21550    most recent M300383200v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by El Alami, M. Articles by Messenguy, F. Search for Related Content PubMed PubMed Citation Articles by El Alami, M. Articles by Messenguy, F. Social Bookmarking                      What's this?

Yeast Epiarginase Regulation, an Enzyme-Enzyme Activity Control

IDENTIFICATION OF RESIDUES OF ORNITHINE CARBAMOYLTRANSFERASE AND ARGINASE RESPONSIBLE FOR ENZYME CATALYTIC AND REGULATORY ACTIVITIES^*

Mohamed El Alami, Evelyne Dubois, Yamina Oudjama, Catherine Tricot, Johan Wouters, Victor Stalon and Francine Messenguy 

From the Université Libre de Bruxelles, Laboratoire de Microbiologie and Institut de Recherches Microbiologiques J. M. Wiame, Ave. Emile Gryzon 1, Brussels 1070, Belgium

In the presence of ornithine and arginine, ornithine carbamoyltransferase (OTCase) and arginase form a one-to-one enzyme complex in which the activity of OTCase is inhibited whereas arginase remains catalytically active. The mechanism by which these nonallosteric enzymes form a stable complex triggered by the binding of their respective substrates raises the question of how such a cooperative association is induced. Analyses of mutations in both enzymes identify residues that are required for their association, some of them being important for catalysis. In arginase, two cysteines at the C terminus of the protein are crucial for its epiarginase function but not for its catalytic activity and trimeric structure. In OTCase, mutations of putative ornithine binding residues, Asp-182, Asn-184, Asn-185, Cys-289, and Glu-256 greatly reduced the affinity for ornithine and impaired the interaction with arginase. The four lysine residues located in the SMG loop, Lys-260, Lys-263, Lys-265, and Lys-268, also play an important role in mediating the sensitivity of OTCase to ornithine and to arginase and appear to be involved in transducing and enhancing the signal given by ornithine for the closure of the catalytic domain.

Received for publication, January 14, 2003 , and in revised form, April 4, 2003.

^* This work was supported by an Action de la Recherche concertée number 98/03-231 between the French Community of Belgium and the Free University of Brussels (U. L. B.) and by the Fonds National de la Recherche Scientifique. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

To whom correspondence should be addressed. Tel.: 32-2-526-7277; Fax: 32-2-526-7273; E-mail: fanarg{at}ulb.ac.be.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				C. Gancedo and C.-L. Flores Moonlighting Proteins in Yeasts Microbiol. Mol. Biol. Rev., March 1, 2008; 72(1): 197 - 210. [Abstract] [Full Text] [PDF]