Skip to main content
Advertisement

Main menu

  • Home
  • Articles
    • Current Issue
    • Fast Forward
    • Latest Articles
    • Special Sections
    • Archive
  • Information
    • Instructions to Authors
    • Submit a Manuscript
    • FAQs
    • For Subscribers
    • Terms & Conditions of Use
    • Permissions
  • Editorial Board
  • Alerts
    • Alerts
    • RSS Feeds
  • Virtual Issues
  • Feedback
  • Submit
  • Other Publications
    • Drug Metabolism and Disposition
    • Journal of Pharmacology and Experimental Therapeutics
    • Molecular Pharmacology
    • Pharmacological Reviews
    • Pharmacology Research & Perspectives
    • ASPET

User menu

  • My alerts
  • Log in
  • My Cart

Search

  • Advanced search
Drug Metabolism & Disposition
  • Other Publications
    • Drug Metabolism and Disposition
    • Journal of Pharmacology and Experimental Therapeutics
    • Molecular Pharmacology
    • Pharmacological Reviews
    • Pharmacology Research & Perspectives
    • ASPET
  • My alerts
  • Log in
  • My Cart
Drug Metabolism & Disposition

Advanced Search

  • Home
  • Articles
    • Current Issue
    • Fast Forward
    • Latest Articles
    • Special Sections
    • Archive
  • Information
    • Instructions to Authors
    • Submit a Manuscript
    • FAQs
    • For Subscribers
    • Terms & Conditions of Use
    • Permissions
  • Editorial Board
  • Alerts
    • Alerts
    • RSS Feeds
  • Virtual Issues
  • Feedback
  • Submit
  • Visit dmd on Facebook
  • Follow dmd on Twitter
  • Follow ASPET on LinkedIn
Research ArticleArticle

Mechanism-Based Inactivation of Cytochrome P450 2B6 by a Novel Terminal Acetylene Inhibitor

Peter W. Fan, Chungang Gu, Sandra A. Marsh and Jeffrey C. Stevens
Drug Metabolism and Disposition January 2003, 31 (1) 28-36; DOI: https://doi.org/10.1124/dmd.31.1.28
Peter W. Fan
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Chungang Gu
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Sandra A. Marsh
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Jeffrey C. Stevens
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • Article
  • Figures & Data
  • Info & Metrics
  • eLetters
  • PDF
Loading

Abstract

N-(3,5-Dichloro-4-pyridyl)-3-(cyclopentyloxy)-4-methoxybenzamide (DCMB) is a known marker substrate for cytochrome P450 2B6. Based on the chemical template of DCMB, a novel terminal acetylene compound,N-(3,5-dichloro-4-pyridyl)-4-methoxy-3-(prop-2-ynyloxy)benzamide (TA) was synthesized and evaluated as a mechanism-based inactivator of P450 2B6. The pseudo first-order inactivation of expressed P450 2B6 by TA was both substrate and time-dependent. The kinetics of inhibition resulted in a maximal rate constant (kinactivation) of 0.09 min−1and an apparent KI of 5.1 μM. Incubation of expressed P450 2B6 with TA and NADPH resulted in a 68% loss in enzyme activity and a concurrent 62% loss in the formation of a reduced carbon monoxide complex, suggesting that heme destruction is the primary mode of enzyme inactivation. Enzyme inactivation of P450 2B6 was not reduced by the presence of 10 mM glutathione and was protected by incubation of excess DCMB with TA. The production of the carboxylic acid metabolite,N-(3,5-Dichloro-4-pyridyl)-3-(2-carboxyethoxy)-4-methoxybenzamide (TA-COOH), during the incubation of TA with 2B6 suggests that inactivation proceeds through a ketene intermediate. For 2B6 inactivation, the partition ratio was approximately 1.5 nmol TA-COOH formed/nmol P450 inactivated. Finally, TA was evaluated for mechanism-based inactivation of P450 3A4, 2C9, 2C19, 2D6, and 2E1 using human liver microsomes. In addition to 2B6, P450 2C forms were also found to be sensitive to TA-mediated inactivation, suggesting that subtle changes in the O-alkyl chain of the parent may be critical for the selectivity of enzyme inactivation.

Footnotes

  • Abbreviations used are::
    P450
    cytochrome P450
    DCMB
    N-(3,5-dichloro-4-pyridyl)-3-(cyclopentyloxy)-4-methoxybenzamide
    TA
    N-(3,5-dichloro-4-pyridyl)-4-methoxy-3-(prop-2-ynyloxy)benzamide (terminal acetylene)
    DCMB-OH
    N-(3,5-dichloro-4-pyridyl)-3-(3-hydroxycyclopentyloxy)-4-methoxybenzamide (hydroxy metabolite of DCMB)
    TA-COOH
    N-(3,5-Dichloro-4-pyridyl)-3-(2-carboxyethoxy)-4-methoxybenzamide
    LC
    liquid chromatography
    MS/MS
    tandem mass spectrometry
    MS
    mass spectrometry
    kinactivation
    maximal rate of inactivation at saturation
    KI
    half-maximal inactivation
    SRM
    selected reaction monitoring
    • Received June 13, 2002.
    • Accepted September 25, 2002.
  • The American Society for Pharmacology and Experimental Therapeutics
View Full Text

 

DMD articles become freely available 12 months after publication, and remain freely available for 5 years. 

Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page. 

 

  • Click here for information on institutional subscriptions.
  • Click here for information on individual ASPET membership.

 

Log in using your username and password

Forgot your user name or password?

Purchase access

You may purchase access to this article. This will require you to create an account if you don't already have one.
PreviousNext
Back to top

In this issue

Drug Metabolism and Disposition: 31 (1)
Drug Metabolism and Disposition
Vol. 31, Issue 1
1 Jan 2003
  • Table of Contents
  • About the Cover
  • Index by author
Download PDF
Article Alerts
Sign In to Email Alerts with your Email Address
Email Article

Thank you for sharing this Drug Metabolism & Disposition article.

NOTE: We request your email address only to inform the recipient that it was you who recommended this article, and that it is not junk mail. We do not retain these email addresses.

Enter multiple addresses on separate lines or separate them with commas.
Mechanism-Based Inactivation of Cytochrome P450 2B6 by a Novel Terminal Acetylene Inhibitor
(Your Name) has forwarded a page to you from Drug Metabolism & Disposition
(Your Name) thought you would be interested in this article in Drug Metabolism & Disposition.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Citation Tools
Research ArticleArticle

Mechanism-Based Inactivation of Cytochrome P450 2B6 by a Novel Terminal Acetylene Inhibitor

Peter W. Fan, Chungang Gu, Sandra A. Marsh and Jeffrey C. Stevens
Drug Metabolism and Disposition January 1, 2003, 31 (1) 28-36; DOI: https://doi.org/10.1124/dmd.31.1.28

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero

Share
Research ArticleArticle

Mechanism-Based Inactivation of Cytochrome P450 2B6 by a Novel Terminal Acetylene Inhibitor

Peter W. Fan, Chungang Gu, Sandra A. Marsh and Jeffrey C. Stevens
Drug Metabolism and Disposition January 1, 2003, 31 (1) 28-36; DOI: https://doi.org/10.1124/dmd.31.1.28
Reddit logo Twitter logo Facebook logo Mendeley logo
  • Tweet Widget
  • Facebook Like
  • Google Plus One

Jump to section

  • Article
    • Abstract
    • Materials and Methods
    • Results
    • Discussion
    • Footnotes
    • References
  • Figures & Data
  • Info & Metrics
  • eLetters
  • PDF

Related Articles

Cited By...

More in this TOC Section

  • Ontogeny of CPPGL
  • Expression of AKR and SDR Isoforms in the Human Intestine
  • Metabolism of Lufotrelvir in Humans
Show more Article

Similar Articles

Advertisement
  • Home
  • Alerts
Facebook   Twitter   LinkedIn   RSS

Navigate

  • Current Issue
  • Fast Forward by date
  • Fast Forward by section
  • Latest Articles
  • Archive
  • Search for Articles
  • Feedback
  • ASPET

More Information

  • About DMD
  • Editorial Board
  • Instructions to Authors
  • Submit a Manuscript
  • Customized Alerts
  • RSS Feeds
  • Subscriptions
  • Permissions
  • Terms & Conditions of Use

ASPET's Other Journals

  • Journal of Pharmacology and Experimental Therapeutics
  • Molecular Pharmacology
  • Pharmacological Reviews
  • Pharmacology Research & Perspectives
ISSN 1521-009X (Online)

Copyright © 2023 by the American Society for Pharmacology and Experimental Therapeutics