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Title: A comparison of substrate dynamics in human CYP2E1 and CYP2A6

Abstract

Considering the dynamic nature of CYPs, methods that reveal information about substrate and enzyme dynamics are necessary to generate predictive models. To compare substrate dynamics in CYP2E1 and CYP2A6, intramolecular isotope effect experiments were conducted, using deuterium labeled substrates: o-xylene, m-xylene, p-xylene, 2,6-dimethylnaphthalene, and 4,4'-dimethylbiphenyl. Competitive intermolecular experiments were also conducted using d{sub 0}- and d{sub 6}-labeled p-xylene. Both CYP2E1 and CYP2A6 displayed full isotope effect expression for o-xylene oxidation and almost complete suppression for dimethylbiphenyl. Interestingly (k {sub H}/k {sub D}){sub obs} for d{sub 3}-p-xylene oxidation ((k {sub H}/k {sub D}){sub obs} = 6.04 and (k {sub H}/k {sub D}){sub obs} = 5.53 for CYP2E1 and CYP2A6, respectively) was only slightly higher than (k {sub H}/k {sub D}){sub obs} for d{sub 3}-dimethylnaphthalene ((k {sub H}/k {sub D}){sub obs} = 5.50 and (k {sub H}/k {sub D}){sub obs} = 4.96, respectively). One explanation is that in some instances (k {sub H}/k {sub D}){sub obs} values are generated by the presence of two substrates-bound simultaneously to the CYP. Speculatively, if this explanation is valid, then intramolecular isotope effect experiments should be useful in the mechanistic investigation of P450 cooperativity.

Authors:
 [1];  [2];  [3];  [3]
  1. Department of Medicinal Chemistry, University of Washington, Box 357610, Seattle, WA 98195 (United States). E-mail: harrelsonj@pacificu.edu
  2. Amgen, South San Francisco, CA 94080 (United States)
  3. Department of Medicinal Chemistry, University of Washington, Box 357610, Seattle, WA 98195 (United States)
Publication Date:
OSTI Identifier:
20857971
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochemical and Biophysical Research Communications; Journal Volume: 352; Journal Issue: 4; Other Information: DOI: 10.1016/j.bbrc.2006.11.071; PII: S0006-291X(06)02523-X; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRONMENTAL POLLUTANT EFFECTS ON LIVING ORGANISMS AND BIOLOGICAL MATERIALS; DEUTERIUM; ENZYMES; INHIBITION; ISOTOPE EFFECTS; OXIDATION; SUBSTRATES; XYLENES

Citation Formats

Harrelson, John P., Henne, Kirk R., Alonso, Darwin O.V., and Nelson, Sidney D.. A comparison of substrate dynamics in human CYP2E1 and CYP2A6. United States: N. p., 2007. Web. doi:10.1016/j.bbrc.2006.11.071.
Harrelson, John P., Henne, Kirk R., Alonso, Darwin O.V., & Nelson, Sidney D.. A comparison of substrate dynamics in human CYP2E1 and CYP2A6. United States. doi:10.1016/j.bbrc.2006.11.071.
Harrelson, John P., Henne, Kirk R., Alonso, Darwin O.V., and Nelson, Sidney D.. Fri . "A comparison of substrate dynamics in human CYP2E1 and CYP2A6". United States. doi:10.1016/j.bbrc.2006.11.071.
@article{osti_20857971,
title = {A comparison of substrate dynamics in human CYP2E1 and CYP2A6},
author = {Harrelson, John P. and Henne, Kirk R. and Alonso, Darwin O.V. and Nelson, Sidney D.},
abstractNote = {Considering the dynamic nature of CYPs, methods that reveal information about substrate and enzyme dynamics are necessary to generate predictive models. To compare substrate dynamics in CYP2E1 and CYP2A6, intramolecular isotope effect experiments were conducted, using deuterium labeled substrates: o-xylene, m-xylene, p-xylene, 2,6-dimethylnaphthalene, and 4,4'-dimethylbiphenyl. Competitive intermolecular experiments were also conducted using d{sub 0}- and d{sub 6}-labeled p-xylene. Both CYP2E1 and CYP2A6 displayed full isotope effect expression for o-xylene oxidation and almost complete suppression for dimethylbiphenyl. Interestingly (k {sub H}/k {sub D}){sub obs} for d{sub 3}-p-xylene oxidation ((k {sub H}/k {sub D}){sub obs} = 6.04 and (k {sub H}/k {sub D}){sub obs} = 5.53 for CYP2E1 and CYP2A6, respectively) was only slightly higher than (k {sub H}/k {sub D}){sub obs} for d{sub 3}-dimethylnaphthalene ((k {sub H}/k {sub D}){sub obs} = 5.50 and (k {sub H}/k {sub D}){sub obs} = 4.96, respectively). One explanation is that in some instances (k {sub H}/k {sub D}){sub obs} values are generated by the presence of two substrates-bound simultaneously to the CYP. Speculatively, if this explanation is valid, then intramolecular isotope effect experiments should be useful in the mechanistic investigation of P450 cooperativity.},
doi = {10.1016/j.bbrc.2006.11.071},
journal = {Biochemical and Biophysical Research Communications},
number = 4,
volume = 352,
place = {United States},
year = {Fri Jan 26 00:00:00 EST 2007},
month = {Fri Jan 26 00:00:00 EST 2007}
}