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 Khan, M. S. Articles by Rosner, W. Search for Related Content PubMed PubMed Citation Articles by Khan, M. S. Articles by Rosner, W. Social Bookmarking                      What's this?

JBC, Vol. 252, Issue 6, 1895-1900, Mar, 1977

Investigation of the binding site of human corticosteroid-binding globulin by affinity labeling. Demonstration of a cysteinyl residue in the binding site

M. S. Khan and W. Rosner

This communication deals with the investigation of the binding site of purified human corticosteroid-binding globulin (CBG) by the method of affinity labeling. The design of the studies necessitated the rapid removal of unbound ligands, followed by assay of the binding capacity of CBG. We were able to accomplish this by demonstrating that CBG absorbed on DEAE-filter discs bound cortisol as if both molecules were in solution. Using this principle, 6beta-bromoprogesterone was shown to react with CBG in a time-dependent and irreversible fashion with a t1/2 = 15 min at 2 degrees. One mol of 6beta-bromo[3H]progesterone reacted with 1 mol of CBG. After completion of the reaction, one of the two sulfhydrul groups in CBG was no longer titratable with Ellman's reagent. The product of the reaction of 6beta-bromoprogesterone with cysteine is progesterone-6-S-L-cysteine. After acid hydrolysis of CBG, which had been incubated with 6beta-bromoprogesterone, a compound which migrated with the same mobility on thin layer chromatography as the model compound was observed. We conclude that 6beta-bromoprogesterone is an affinity label for CBG and that a cysteinyl residue is present in the binding site.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				O. E. Janssen, S. T. Astner, H. Grasberger, S. K. Gunn, and S. Refetoff Identification of Thyroxine-Binding Globulin-San Diego in a Family from Houston and Its Characterization by in Vitro Expression Using Xenopus Oocytes J. Clin. Endocrinol. Metab., January 1, 2000; 85(1): 368 - 372. [Abstract] [Full Text]

				H. Grasberger, C. Buettner, and O. E. Janssen Modularity of Serpins. A BIFUNCTIONAL CHIMERA POSSESSING alpha 1-PROTEINASE INHIBITOR AND THYROXINE-BINDING GLOBULIN PROPERTIES J. Biol. Chem., May 21, 1999; 274(21): 15046 - 15051. [Abstract] [Full Text] [PDF]