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 Schopfer, L. M. Articles by Massey, V. Search for Related Content PubMed PubMed Citation Articles by Schopfer, L. M. Articles by Massey, V. Social Bookmarking                      What's this?

J. Biol. Chem., Vol. 266, Issue 20, 13080-13085, Jul, 1991

Interpretation of the spectra observed during oxidation of p- hydroxybenzoate hydroxylase reconstituted with modified flavins

LM Schopfer, A Wessiak and V Massey
Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor 48109-0606.

Oxidation of reduced p-hydroxybenzoate hydroxylase by oxygen in the presence of 2,4-dihydroxybenzoate and azide proceeds via three well established intermediates. Reconstitution of the apoprotein with either 8-thiophenyl-FAD, 8-fluoro-FAD, 8-chloro-FAD, or 8-sulfonyl-FAD does not alter this sequence of events. However, the peak positions of the intermediate spectra are somewhat shifted relative to those of native enzyme. Comparison of the spectra for intermediates II and III leads to the conclusion that the spectrum for intermediate II is a composite. One component is the spectrum of an intermediate III-like species, and the other appears to be related to the substrate. The substrate component is pH-dependent, having an absorbance maximum of 386 nm (extinction, approximately 6,000 M-1 cm-1) at pH 6.6 which shifts to approximately 430 nm (extinction, approximately 11-13,000 M-1 cm-1) at pH 9.2, with a pK of 7.9. The pH dependence for the spectrum of the substrate component combined with the pH independence of the intermediate III-like spectrum satisfactorily accounts for the pH dependence observed for intermediate II, including the fact that the high pH spectrum of native intermediate II is qualitatively quite different from that of 8-sulfonyl-FAD intermediate II.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				B. A. Palfey, Y. V. S. N. Murthy, and V. Massey Altered Balance of Half-reactions in p-Hydroxybenzoate Hydroxylase Caused by Substituting the 2'-Carbon of FAD with Fluorine J. Biol. Chem., June 13, 2003; 278(25): 22210 - 22216. [Abstract] [Full Text] [PDF]

				W. A. Suske, W. J. H. van Berkel, and H.-P. E. Kohler Catalytic Mechanism of 2-Hydroxybiphenyl 3-Monooxygenase, a Flavoprotein from Pseudomonas azelaica HBP1 J. Biol. Chem., November 19, 1999; 274(47): 33355 - 33365. [Abstract] [Full Text] [PDF]