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 Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Weiner, H. Articles by Koshland, D. E. Search for Related Content PubMed PubMed Citation Articles by Weiner, H. Articles by Koshland, D. E., Jr. Social Bookmarking                      What's this?

A Change in Specificity of Chymotrypsin Caused by Chemical Modification of Methionine Residues

From the ¹ From the Biology Department, Brookhaven National Laboratory, Upton, New York

The specificity patterns of chymotrypsins in which the methionine residues have been converted to the sulfoxide have been examined relative to the native enzyme. When the surface methionine residue 3 residues away from the active serine is oxidized, the specificity pattern is quite similar to the native enzyme as judged by the relative rates of hydrolysis of ester and peptide substrates. When both methionine residues are oxidized to the sulfoxide, however, notable changes of the ratios occur. For example, the acetyltyrosinamide activity becomes undetectable, decreased by a factor of over 400, whereas the acetyltyrosine ethyl ester activity decreases by a factor of 4. The change in specificity is not related in a simple way either to a chemical property such as carbon-nitrogen versus the carbon-oxygen bond nor to the size of the substrate. Moreover, the binding properties for many substrates and all-or-none assay are changed very little. A plausible explanation for the observations is that the oxidation of the interior methionine residue does not change the basic catalytic power of the enzyme but does cause subtle changes in the relationship between substrate and enzyme which affects its specificity.

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

This article has been cited by other articles:

				S. M. Van Patten, E. Hanson, R. Bernasconi, K. Zhang, P. Manavalan, E. S. Cole, J. M. McPherson, and T. Edmunds Oxidation of Methionine Residues in Antithrombin. EFFECTS ON BIOLOGICAL ACTIVITY AND HEPARIN BINDING J. Biol. Chem., April 9, 1999; 274(15): 10268 - 10276. [Abstract] [Full Text] [PDF]

				H. Neurath, K. A. Walsh, and W. P. Winter Evolution of Structure and Function of Proteases: Amino acid sequences of proteolytic enzymes reflect phylogenetic relationships Science, December 29, 1967; 158(3809): 1638 - 1644. [Abstract] [PDF]