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

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted 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 Joyce, B. K. Articles by Himes, R. H. Search for Related Content PubMed PubMed Citation Articles by Joyce, B. K. Articles by Himes, R. H. Social Bookmarking                      What's this?

Formyltetrahydrofolate Synthetase

INITIAL VELOCITY AND PRODUCT INHIBITION STUDIES

From the ¹ From the Department of Microbiology and the Department of Comparative Biochemistry and Physiology, University of Kansas, Lawrence, Kansas 66044

The order of binding of the substrates to formyltetrahydrofolate synthetase from Clostridium cylindrosporum was examined by determining the initial velocity of the reaction under varied conditions of substrate and product concentrations. The data from experiments in which the changing fixed substrate was varied in concentration from a value below its K_m to a saturating concentration gave intersecting plots of 1/v against 1/s. The results indicate that the substrates bind in a random fashion and that all substrates must be bound before any products are released. In addition, the binding constants of the substrates in the ternary complexes are slightly different from those in the quaternary complex.

Inhibition by the three products was examined under varied conditions of substrate concentrations, and the results were found to be most consistent with a random mechanism in which certain "dead end" complexes are formed. Under some conditions orthophosphate showed uncompetitive inhibition. This finding indicates that the inhibition by orthophosphate is more than simple product inhibition.

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

This article has been cited by other articles:

				J. M. Jez and R. E. Cahoon Kinetic Mechanism of Glutathione Synthetase from Arabidopsis thaliana J. Biol. Chem., October 8, 2004; 279(41): 42726 - 42731. [Abstract] [Full Text] [PDF]