JBC Advanced Glycation Endproducts

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Bell-Parikh, L. C.
Right arrow Articles by Guengerich, F. P.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Bell-Parikh, L. C.
Right arrow Articles by Guengerich, F. P.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?

J Biol Chem, Vol. 274, Issue 34, 23833-23840, August 20, 1999

Kinetics of Cytochrome P450 2E1-Catalyzed Oxidation of Ethanol to Acetic Acid via Acetaldehyde

L. Chastine Bell-Parikh and F. Peter Guengerich

From the Department of Biochemistry and Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146

The P450 2E1-catalyzed oxidation of ethanol to acetaldehyde is characterized by a kinetic deuterium isotope effect that increases Km with no effect on kcat, and rate-limiting product release has been proposed to account for the lack of an isotope effect on kcat (Bell, L. C., and Guengerich, F. P. (1997) J. Biol. Chem. 272, 29643-29651). Acetaldehyde is also a substrate for P450 2E1 oxidation to acetic acid, and kcat/Km for this reaction is at least 1 order of magnitude greater than that for ethanol oxidation to acetaldehyde. Acetic acid accounts for 90% of the products generated from ethanol in a 10-min reaction, and the contribution of this second oxidation has been overlooked in many previous studies. The noncompetitive intermolecular kinetic hydrogen isotope effects on acetaldehyde oxidation to acetic acid (H(kcat/Km)/D(kcat/Km) = 4.5, and Dkcat = 1.5) are comparable with the isotope effects typically observed for ethanol oxidation to acetaldehyde, and kcat is similar for both reactions, suggesting a possible common catalytic mechanism. Rapid quench kinetic experiments indicate that acetic acid is formed rapidly from added acetaldehyde (~450 min-1) with burst kinetics. Pulse-chase experiments reveal that, at a subsaturating concentration of ethanol, ~90% of the acetaldehyde intermediate is directly converted to acetic acid without dissociation from the enzyme active site. Competition experiments suggest that P450 2E1 binds acetic acid and acetaldehyde with relatively high Kd values, which preclude simple tight binding as an explanation for rate-limiting product release. The existence of a rate-determining step between product formation and release is postulated. Also proposed is a conformational change in P450 2E1 occurring during the course of oxidation and the discrimination of P450 2E1 between acetaldehyde and its hydrated form, the gem-diol. This multistep P450 reaction is characterized by kinetic control of individual reaction steps and by loose binding of all ligands.

Copyright © 1999 by The American Society for Biochemistry and Molecular Biology, Inc.
Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?


This article has been cited by other articles:


Home page
 Toxicol Ind HealthHome page
M. Gulec, A. Songur, S. Sahin, O. A Ozen, M. Sarsilmaz, and O. Akyol
Antioxidant enzyme activities and lipid peroxidation products in heart tissue of subacute and subchronic formaldehyde-exposed rats: a preliminary study
Toxicology and Industrial Health, April 1, 2006; 22(3): 117 - 124.
[Abstract] [PDF]

Home page
 J. Biol. Chem.Home page
J. A. Krauser and F. P. Guengerich
Cytochrome P450 3A4-catalyzed Testosterone 6{beta}-Hydroxylation Stereochemistry, Kinetic Deuterium Isotope Effects, and Rate-limiting Steps
J. Biol. Chem., May 20, 2005; 280(20): 19496 - 19506.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
C.-H. Yun, K.-H. Kim, M. W. Calcutt, and F. P. Guengerich
Kinetic Analysis of Oxidation of Coumarins by Human Cytochrome P450 2A6
J. Biol. Chem., April 1, 2005; 280(13): 12279 - 12291.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
F. P. Guengerich, G. P. Miller, I. H. Hanna, H. Sato, and M. V. Martin
Oxidation of Methoxyphenethylamines by Cytochrome P450 2D6. ANALYSIS OF RATE-LIMITING STEPS
J. Biol. Chem., September 6, 2002; 277(37): 33711 - 33719.
[Abstract] [Full Text] [PDF]

Home page
 Appl. Environ. Microbiol.Home page
B. Buhler, B. Witholt, B. Hauer, and A. Schmid
Characterization and Application of Xylene Monooxygenase for Multistep Biocatalysis
Appl. Envir. Microbiol., February 1, 2002; 68(2): 560 - 568.
[Abstract] [Full Text] [PDF]

Home page
 Toxicol SciHome page
T. R. Van Vleet, D. W. Bombick, and R. A. Coulombe Jr.
Inhibition of Human Cytochrome P450 2E1 by Nicotine, Cotinine, and Aqueous Cigarette Tar Extract in Vitro
Toxicol. Sci., December 1, 2001; 64(2): 185 - 191.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
S. Kominami, A. Owaki, T. Iwanaga, H. Tagashira-Ikushiro, and T. Yamazaki
The Rate-determining Step in P450 C21-catalyzing Reactions in a Membrane-reconstituted System
J. Biol. Chem., March 30, 2001; 276(14): 10753 - 10758.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
 All ASBMB Journals   Molecular and Cellular Proteomics 
 Journal of Lipid Research   ASBMB Today 
Copyright © 1999 by the American Society for Biochemistry and Molecular Biology.