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

This Article Full Text Full Text (PDF) 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 McCudden, C. R. Articles by Powers-Lee, S. G. Search for Related Content PubMed PubMed Citation Articles by McCudden, C. R. Articles by Powers-Lee, S. G. Social Bookmarking                      What's this?

Volume 271, Number 30, Issue of July 26, 1996 pp. 18285-18294
©1996 by The American Society for Biochemistry and Molecular Biology, Inc.

---

Required Allosteric Effector Site for N-Acetylglutamate on Carbamoyl-Phosphate Synthetase I

(Received for publication, September 5, 1995, and in revised form, May 1, 1996)

From the Department of Biology, Northeastern University, Boston, Massachusetts 02115

Carbamoyl-phosphate synthetase I (CPSase I) catalyzes the entry and rate-limiting step in the urea cycle, the pathway by which mammals detoxify ammonia. One facet of CPSase I regulation is a requirement for N-acetylglutamate (AGA), which induces an active enzyme conformation and does not participate directly in the chemical reaction. We have utilized labeling with carbodiimide-activated [¹⁴C]AGA to identify peptides 120-127, 234-237, 625-630, and 1351-1356 as potentially being near the binding site for AGA. Identification of peptide 1351-1356 confirms the previous demonstration (Rodriquez-Aparicio, L. B., Guadalajara, A. M., and Rubio, V. (1989) Biochemistry 28, 3070-3074) that the C-terminal region is involved in binding AGA. Identification of peptides 120-127 and 234-237 constitutes the first evidence that the N-terminal region of the synthetase is involved in ligand binding. Since peptides 631-638 and 1327-1348 have been identified near the ATP site of CPSase I (Potter, M. D., and Powers-Lee, S. G. (1992) J. Biol. Chem. 267, 2023-2031), the present finding of involvement of peptides 625-630 and 1351-1356 at an ``allosteric'' activator site was unexpected. The idea that portions of the AGA effector site might be derived from an ancestral glutamine substrate site via a gene duplication and diversification event was considered.

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

This article has been cited by other articles:

				D. R. Evans and H. I. Guy Mammalian Pyrimidine Biosynthesis: Fresh Insights into an Ancient Pathway J. Biol. Chem., August 6, 2004; 279(32): 33035 - 33038. [Full Text] [PDF]

				B. Eroglu and S. G. Powers-Lee Unmasking a Functional Allosteric Domain in an Allosterically Nonresponsive Carbamoyl-phosphate Synthetase J. Biol. Chem., November 15, 2002; 277(47): 45466 - 45472. [Abstract] [Full Text] [PDF]

				N. Sahay, H. I. Guy, X. Liu, and D. R. Evans Regulation of an Escherichia coli/Mammalian Chimeric Carbamoyl-phosphate Synthetase J. Biol. Chem., November 20, 1998; 273(47): 31195 - 31202. [Abstract] [Full Text] [PDF]

				E. H. Van Beers, E. H.H.M. Rings, G. Posthuma, M. A. Dingemanse, J. A.M.J. Taminiau, H. S.A. Heymans, A. W.C. Einerhand, H. A. Buller, and J. Dekker Intestinal Carbamoyl Phosphate Synthase I in Human and Rat: Expression During Development Shows Species Differences and Mosaic Expression in Duodenum of Both Species J. Histochem. Cytochem., February 1, 1998; 46(2): 231 - 240. [Abstract] [Full Text]

				H. I. Guy and D. R. Evans Trapping an Activated Conformation of Mammalian Carbamyl-phosphate Synthetase J. Biol. Chem., August 8, 1997; 272(32): 19906 - 19912. [Abstract] [Full Text] [PDF]