Characterization of the in vitro binding and inhibition kinetics of primary amine oxidase/vascular adhesion protein-1 by glucosamine.
BACKGROUND
Primary-amine oxidase (PrAO) catalyzes the oxidative deamination of endogenous and exogenous primary amines and also functions, in some tissues, as an inflammation-inducible endothelial factor, known as vascular adhesion protein-1. VAP-1 mediates the slow rolling and adhesion of lymphocytes to endothelial cells in a number of inflammatory conditions, including inflammation of the synovium.


METHODS
Glucosamine binding to the enzyme was assessed spectrofluorometrically and the kinetics of inhibition of PrAO were determined spectrophotometrically through the use of direct or coupled assays, in the presence of different substrates.


RESULTS
Glucosamine is not a substrate for PrAO, but acts as a time-dependent inhibitor of PrAO activity, displaying mixed inhibition kinetics. The observed inhibition and binding were augmented in the presence of H(2)O(2).


CONCLUSIONS
Significant in vitro effects on PrAO require glucosamine in the millimolar concentration range and it is not clear at this stage whether a low but persistent level of PrAO inhibition might contribute to the anti-arthritic response.


CONCLUSIONS
This work was aimed at characterizing the interactions of PrAO/VAP-1 with glucosamine, a widely used "over-the-counter" supplement for the treatment of osteoarthritis.
School of Biochemistry and Immunology, Trinity College Dublin, Ireland. oliviera@tcd.ie
Aldo
A
Olivieri
Keith F
KF
Tipton
Jeff
J
O'Sullivan
D006631:Amine Oxidase (Copper-Containing) / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D002448:Cell Adhesion; D003641:Deamination; D042783:Endothelial Cells / Q000378:metabolism; D005944:Glucosamine / Q000378:metabolism* / Q000494:pharmacology*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D036904:Leukocyte Rolling; D008214:Lymphocytes / Q000378:metabolism; D010003:Osteoarthritis / Q000188:drug therapy; D010084:Oxidation-Reduction
D006861:Hydrogen Peroxide; D006631:Amine Oxidase (Copper-Containing); D005944:Glucosamine