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

Inflammation Disrupts Memory - What Can You Do to Protect Your Brain?

Artificial sweeteners linked to risk of weight gain, heart disease and other health issues

All About Ginkgo Biloba: Benefits of This Timeless Herbal Supplement

Yarrow Oil: Here's Why It Deserves a Place in Your First-Aid Kit

Vitamin D supplement use associated with lower risk of breast cancer

Carnitine deficiency suggested as contributor to autism

Hop Oil: A Safe Sleep Aide

Lutein — An Important Nutrient for Eye and Brain Health

White Camphor Oil: The Purest Camphor Oil

Taurine: Facts About This Crucial Amino Acid

 
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
Ultra EPA  - Fish Oil Mitochondria Ignite™ with NT Factor® Vitamin D3 Extreme™


Article Comments



Be the first to comment on this article!

Post a Comment


 
NAD+ Ignite with Niagen

Featured Products

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
FibroSleep™ FibroSleep™
The All-in-One Natural Sleep Aid
Vitamin D3 Extreme™ Vitamin D3 Extreme™
50,000 IU Vitamin D3 - Prescription Strength
Mitochondria Ignite™ with NT Factor® Mitochondria Ignite™ with NT Factor®
Reduce Fatigue up to 45%

Natural Remedies

How Glutathione Can Save Your Life How Glutathione Can Save Your Life
Pioneer Scientists Uncover a Revolutionary Neuroprotective Supplement for Nerve Health Pioneer Scientists Uncover a Revolutionary Neuroprotective Supplement for Nerve Health
Carry a Massage Therapist in Your Pocket Carry a Massage Therapist in Your Pocket
Green Coffee Extract: Unique Obesity Intervention Green Coffee Extract: Unique Obesity Intervention
The Super Antioxidant for Brain, Joint and Heart Health The Super Antioxidant for Brain, Joint and Heart Health

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