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Exp Clin Endocrinol Diabetes 1997; 105(5): 304-307
DOI: 10.1055/s-0029-1211769
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© J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York

Involvement of tryptophan in the structural alterations of the rat ovarian LH/hCG receptor

J. Kolena1 , S. Scsuková1 , M. Tatara2 , J. Vranová1 , M. Ježová1
  • 1Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava
  • 2Institute of Preventive and Clinical Medicine, Bratislava, Slovak Republic
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Publication History

Publication Date:
14 July 2009 (online)

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Summary

Treatment of the rat ovarian membrane-bound and Triton X-100 solubilized LH/hCG receptor with the tryptophanspecific reagents N-bromosuccinimide (NBS) and 2-hydroxy-5-nitrobenzyl bromide (HNB-Br) resulted in inactivation of the receptor to bind hCG Fluorescence quenching studies indicated that oxidation of tryptophan residues by NBS decreased the accessibility of fluorophores for acrylamide. Preceding binding of hCG to receptor sites was found to protect fluorophores from NBS action. Modification of tryptophan residues was associated with alteration in the rigidity of ovarian membranes and with destabilization of the LH/hCG receptor structure. The results suggest that tryptophan residue is essential for hCG binding to the receptor.

Key words

LH/hCG receptor - tryptophan residue - fluorescence quenching - fluorescence polarization - thermal inactivation