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

INTERACTIONS BETWEEN CYP2C9 AND CYP2C19 IN RECONSTITUTED BINARY SYSTEMS INFLUENCE THEIR CATALYTIC ACTIVITY: POSSIBLE RATIONALE FOR THE INABILITY OF CYP2C19 TO CATALYZE METHOXYCHLOR DEMETHYLATION IN HUMAN LIVER MICROSOMES

Eszter Hazai and David Kupfer
Drug Metabolism and Disposition January 2005, 33 (1) 157-164; DOI: https://doi.org/10.1124/dmd.104.001578
Eszter Hazai
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
David Kupfer
  • 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

Previous studies in our laboratory showed that among cDNA-expressed human cytochrome P450 (P450) supersomes, CYP2C19 was the most active in methoxychlor-O-demethylation (Hu et al., 2004). However, based on the lack of inhibition of methoxychlor-O-demethylation by monoclonal anti-CYP2C19 antibodies in human liver microsomes (HLM), CYP2C19 did not seem to catalyze that reaction in HLM. By contrast, CYP2C9, much less active than CYP2C19 in supersomes, was the most active in HLM. The current study examines whether the lack of methoxychlor-O-demethylation by CYP2C19 in HLM was due to CYP2C19 exhibiting inferior competition for the NADPH-cytochrome P450 reductase (CPR) versus CYP2C9 and explores the interactions between CYP2C9 and CYP2C19 in a singular and binary complex of a reconstituted system. When reconstituted with CPR, cytochrome b5, and lipid, purified CYP2C19 and CYP2C9 catalyzed methoxychlor-O-demethylation. However, whereas equimolar CPR to CYP2C9 supported maximal rates of methoxychlor demethylation and diclofenac hydroxylation, the rate of methoxychlor demethylation by CYP2C19 was not fully saturated, even with a 9-fold molar excess of CPR over CYP2C19. This behavior of CYP2C19 was also observed with S-mephenytoin as the substrate. When a binary reconstitution system was prepared by mixing CYP2C9 and CYP2C19 enzymes, methoxychlor-O-demethylation and S-mephenytoin hydroxylation by CYP2C19 were dramatically inhibited. Inhibition depended on the amount of CPR and substrate used. By contrast, in the incubation containing CYP2C9, diclofenac hydroxylation was activated by the presence of CYP2C19. These results show that interactions among P450 enzymes can modulate their catalytic rates, which depend on the substrate undergoing metabolism.

Footnotes

  • doi:10.1124/dmd.104.001578.

  • ABBREVIATIONS: P450, cytochrome P450; CPR, cytochrome P450 reductase; HLM, human liver microsome(s); DLPC, 1,2-didodecanoyl-racglycero-3-phosphocholine; HPLC, high-performance liquid chromatography; PTFE, polytetrafluoroethylene; mono-OH-M, 1,1,1-trichloro-2-(4-hydroxyphenyl)-2-(4-methoxyphenyl)ethane; bis-OH-M, 1,1,1-trichloro-2,2-bis(4-hydroxyphenyl)ethane.

    • Received July 28, 2004.
    • Accepted October 8, 2004.
  • 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: 33 (1)
Drug Metabolism and Disposition
Vol. 33, Issue 1
1 Jan 2005
  • 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.
INTERACTIONS BETWEEN CYP2C9 AND CYP2C19 IN RECONSTITUTED BINARY SYSTEMS INFLUENCE THEIR CATALYTIC ACTIVITY: POSSIBLE RATIONALE FOR THE INABILITY OF CYP2C19 TO CATALYZE METHOXYCHLOR DEMETHYLATION IN HUMAN LIVER MICROSOMES
(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

INTERACTIONS BETWEEN CYP2C9 AND CYP2C19 IN RECONSTITUTED BINARY SYSTEMS INFLUENCE THEIR CATALYTIC ACTIVITY: POSSIBLE RATIONALE FOR THE INABILITY OF CYP2C19 TO CATALYZE METHOXYCHLOR DEMETHYLATION IN HUMAN LIVER MICROSOMES

Eszter Hazai and David Kupfer
Drug Metabolism and Disposition January 1, 2005, 33 (1) 157-164; DOI: https://doi.org/10.1124/dmd.104.001578

Citation Manager Formats

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

Share
Research ArticleArticle

INTERACTIONS BETWEEN CYP2C9 AND CYP2C19 IN RECONSTITUTED BINARY SYSTEMS INFLUENCE THEIR CATALYTIC ACTIVITY: POSSIBLE RATIONALE FOR THE INABILITY OF CYP2C19 TO CATALYZE METHOXYCHLOR DEMETHYLATION IN HUMAN LIVER MICROSOMES

Eszter Hazai and David Kupfer
Drug Metabolism and Disposition January 1, 2005, 33 (1) 157-164; DOI: https://doi.org/10.1124/dmd.104.001578
del.icio.us logo Digg logo Reddit logo Twitter logo Facebook logo Google 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

  • Warfarin PBPK Model with TMDD Mechanism
  • Identification of payload-containing catabolites of ADCs
  • PK Interactions of Licorice with Cytochrome P450s
Show more Articles

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