ProHealth health Vitamin and Natural Supplement Store and Health
Home  |  Log In  |  My Account  |  View Cart  View Your ProHealth Vitamin and Supplement Shopping Cart
800-366-6056  |  Contact Us  |  Help
Facebook Google Plus
Fibromyalgia  Chronic Fatigue Syndrome & M.E.  Lyme Disease  Natural Wellness  Supplement News  Forums  Our Story
Store     Brands   |   A-Z Index   |   Best Sellers   |   New Products   |   Deals & Specials   |   Under $10   |   SmartSavings Club

Trending News

Can Autoimmune Conditions be Reversed? Researchers Make a Surprising Discovery

How One Tiny Molecule Turned into One Huge Health Breakthrough

Nutrients Boost Stem Cell Function

Humans have three times more brown body fat

B12 Proven Essential for Every Cell

Soy isoflavones may benefit breast cancer patients

How B Vitamins Improve Brain Health, Cognition, Psychiatric Problems and Mood Disorders

Dietary prebiotics improve sleep, buffer impacts of stress, says study

Exercises to Help Prevent Urinary Incontinence

Higher red blood cell omega 3 levels in women linked to lower risk of mortality over 14.9 year media...

 
Print Page
Email Article

Abstract: Inhibition of human liver catechol-O-methyltransferase by tea catechins and their metabolites: Structure-activity relationship and molecular-modeling studies

  [ 67 votes ]   [ Discuss This Article ]
www.ProHealth.com • May 2, 2005


Biochem Pharmacol. 2005 May 15;69(10):1523-31. Chen D, Wang CY, Lambert JD, Ai N, Welsh WJ, Yang CS. Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers University, 164 Frelinghuysen Road, Piscataway, NJ 08854, USA. (-)-Epigallocatechin-3-gallate (EGCG) is the major polyphenol present in green tea. We previously demonstrated that EGCG was both a substrate and potent inhibitor of human liver cytosolic catechol-O-methyltransferease (COMT). We now report the structure-activity relationship for the inhibition of COMT-catalyzed O-methylation of catecholestrogens in human liver cytosol by tea catechins and some of their metabolites. The most potent inhibitors were catechins with a galloyl-type D-ring, including EGCG (IC(50)=0.07muM), 4'-O-methyl-EGCG (IC(50)=0.10muM), 4',4'-di-O-methyl-EGCG (4',4'-DiMeEGCG) (IC(50)=0.15muM), and (-)-epicatechin-3-gallate (ECG) (IC(50)=0.20muM). Catechins without the D-ring showed two to three orders of magnitude less inhibitory potency. Enzyme kinetic analyses revealed that EGCG behaved as a mixed inhibitor, whereas 4',4'-di-O-methyl-EGCG exhibited competitive kinetics for the S-adenosylmethionine (SAM), and noncompetitive kinetics for the catechol binding site. These compounds may represent a new type of COMT inhibitor. In silico molecular-modeling studies using a homology model of human COMT were conducted to aid in the understanding the catalytic and inhibitory mechanisms. Either D-ring or B-ring of EGCG could be accommodated to the substrate binding pocket of human COMT. However, the close proximity (2.6A) of 4'-OH to the critical residue Lys144, the higher acidity of the hydroxyl groups of the D-ring, and the hydrophobic interactions between the D-ring and residues in the binding pocket greatly facilitated the interaction of the D-ring with the enzyme, and resulted in increased inhibitory potency. These results provide mechanistic insight into the inhibition of COMT by commonly consumed tea catechins. PMID: 15857617 [PubMed - in process]




Post a Comment

Featured Products From the ProHealth Store
Vitamin D3 Extreme™ Ultra ATP+, Double Strength FibroSleep™

Looking for Vitamins, Herbs and Supplements?
Search the ProHealth Store for Hundreds of Natural Health Products


Article Comments



Be the first to comment on this article!

Post a Comment


 
NAD+ Ignite with Niagen

Featured Products

Optimized Curcumin Longvida® Optimized Curcumin Longvida®
Supports Cognition, Memory & Overall Health
Energy NADH™ 12.5mg Energy NADH™ 12.5mg
Improve Energy & Cognitive Function
Ultra EPA  - Fish Oil Ultra EPA - Fish Oil
Ultra concentrated source of essential fish oils
Ultra ATP+, Double Strength Ultra ATP+, Double Strength
Get energized with malic acid & magnesium
Vitamin D3 Extreme™ Vitamin D3 Extreme™
50,000 IU Vitamin D3 - Prescription Strength

Natural Remedies

Quercetin: Natural Support for Allergy & Inflammation Relief and More Quercetin: Natural Support for Allergy & Inflammation Relief and More
Could a B-12 Deficiency Be Causing Your Symptoms? Could a B-12 Deficiency Be Causing Your Symptoms?
How Glutathione Can Save Your Life How Glutathione Can Save Your Life
The Fast-Acting Solution for Healthy Digestive Function The Fast-Acting Solution for Healthy Digestive Function
Research Links Green Tea to Weight Loss Research Links Green Tea to Weight Loss

CONTACT US
ProHealth, Inc.
555 Maple Ave
Carpinteria, CA 93013
(800) 366-6056  |  Email

· Become a Wholesaler
· Vendor Inquiries
· Affiliate Program
SHOP WITH CONFIDENCE
Credit Card Processing
SUBSCRIBE TO OUR NEWSLETTERS
Get the latest news about Fibromyalgia, M.E/Chronic Fatigue Syndrome, Lyme Disease and Natural Wellness

CONNECT WITH US ProHealth on Facebook  ProHealth on Twitter  ProHealth on Pinterest  ProHealth on Google Plus

© 2017 ProHealth, Inc. All rights reserved. Pain Tracker App  |  Store  |  Customer Service  |  Guarantee  |  Privacy  |  Contact Us  |  Library  |  RSS  |  Site Map