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 Churchich, J. E. Articles by Oh, K. J. Search for Related Content PubMed PubMed Citation Articles by Churchich, J. E. Articles by Oh, K. J. Social Bookmarking                      What's this?

JBC, Vol. 250, Issue 19, 7722-7727, Oct, 1975

Nonequivalent binding sites in cystathionase. Nanosecond and steady fluorescence studies

J. E. Churchich, T. Beeler and K. J. Oh

The analogs P-pyridoxyl-L-alanine and P-pyridoxyl-L-homoserine bind to the apoprotein of the enzyme cystathionase and inhibit the reactivation of enzymatic activity after addition of pyridoxyl-5-P. The binding of the inhibitors was monitored by measuring the fluorescence emitted by the P-pyridoxyl moiety at 395 nm (excitation 325 nm). The fluorometric titration results indicate the presence of nonequivalent binding sites in the apoprotein. A model based on two classes of independent binding sites fits the fluorometric data reasonably well. The presence of nonequivalent fluorescent sites in reduced cystathionase was also detected by nanosecond spectroscopy. In contrast to the model compound P-pyridoxyl-epsilon-lysine (tau equals 2.6 ns), the P-pyridoxyl residues of cystathionase display multiexponential fluorescence decay. Two fluorescence lifetimes (tau2 equals 4.1 ns and tau2 equals 15 ns) fit the deconvoluted decay results obtained by pulse fluorimetry. It is proposed that the P-pyridoxyl chromophores of reduced cystathionase have different environments.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				S. Yamagata, T. Yasugahira, Y. Okuda, and T. Iwama Conversion of the Aminocrotonate Intermediate Limits the Rate of {gamma}-Elimination Reaction Catalyzed by L-Cystathionine {gamma}-lyase of the Yeast Saccharomyces cerevisiae J. Biochem., October 1, 2003; 134(4): 607 - 613. [Abstract] [Full Text] [PDF]

				C. Steegborn, T. Clausen, P. Sondermann, U. Jacob, M. Worbs, S. Marinkovic, R. Huber, and M. C. Wahl Kinetics and Inhibition of Recombinant Human Cystathionine gamma -Lyase. TOWARD THE RATIONAL CONTROL OF TRANSSULFURATION J. Biol. Chem., April 30, 1999; 274(18): 12675 - 12684. [Abstract] [Full Text] [PDF]