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

J. Biol. Chem., Vol. 279, Issue 22, 23710-23718, May 28, 2004

This Article Full Text Full Text (PDF) All Versions of this Article: 279/22/23710    most recent M401086200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted 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 Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Cotton, N. J. H. Articles by Parson, W. W. Search for Related Content PubMed PubMed Citation Articles by Cotton, N. J. H. Articles by Parson, W. W. Social Bookmarking                      What's this?

Oxidative Inhibition of Human Soluble Catechol-O-methyltransferase^*

Naomi J. H. Cotton¶, Barry Stoddard, and William W. Parson||

From the Department of Biochemistry, University of Washington, Seattle, Washington 98195-7350 and Fred Hutchinson Cancer Research Center, Box 358080, Seattle, Washington 98109-8080

A common polymorphism in the human gene for catechol-O-methyltransferase results in replacement of Val-108 by Met in the soluble form of the protein (s-COMT) and has been linked to breast cancer and neuropsychiatric disorders. The 108M and 108V variants are reported to differ in their thermal stability, with 108M COMT losing catalytic activity more rapidly. Because human s-COMT contains seven cysteine residues and includes CXXC and CXXS motifs that are associated with thiol-disulfide redox reactions, we examined the effects of reducing and oxidizing conditions on the enzyme. In the absence of a reductant 108M s-COMT lost activity more rapidly than 108V, whereas in the presence of 4 mM dithiothreitol (DTT) we found no significant differences in the stability of the two variants at 37 °C. DTT also restored most of the activity that was lost upon incubation at 37 °C in the absence of DTT. Mass spectrometry showed that cysteines 188 and 191 formed an intramolecular disulfide bond when s-COMT was incubated with oxidized glutathione, whereas cysteines 69, 95, 157, and 173 formed protein-glutathione adducts. Replacing Cys-95 by serine protected 108M s-COMT against inactivation in the absence of a reductant; C33S and Cys-188 mutations had little effect, and C69S was destabilizing. The sequences surrounding the reactive cysteine residues of human s-COMT and other proteins that form glutathione adducts at identified sites all include Pro and/or Gly and most include a hydrogen-bonding residue, suggesting that glutathiolation at conserved sites plays a physiologically important role.

Received for publication, January 30, 2004 , and in revised form, March 15, 2004.

^* This work was supported in part by National Institutes of Health Grant R01GM49857. 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.

^¶ Supported by a National Institutes of Health pre-doctoral training grant in molecular biophysics (5-T32-GM08268) and by a grant from the University of Washington Alcoholism and Drug Abuse Institute. 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: Dept. of Biochemistry, Box 357350, University of Washington, Seattle, WA 98195-7350. Tel.: 206-543-1743; Fax: 206-685-1792; E-mail: parsonb{at}u.washington.edu.

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

This article has been cited by other articles:

				D. M. Townsend S-Glutathionylation: Indicator of Cell Stress and Regulator of the Unfolded Protein Response Mol. Interv., December 1, 2007; 7(6): 313 - 324. [Abstract] [Full Text] [PDF]