Interaction of l-lysine and soluble elastin with the semicarbazide-sensitive amine oxidase in the context of its vascularadhesion and tissue maturation functions, BBA -Proteins and Proteomics (2010), doi: 10.1016/j.bbapap.2010 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Corresponding author: Aldo Olivieri, oliviera@tcd.ie
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AbstractThe copper-containing quinoenzyme semicarbazide-sensitive amine oxidase (EC 1.4.3.21; SSAO) is a multifunctional protein. In some tissues, such as the endothelium, it also acts as vascular-adhesion protein 1 (VAP-1), which is involved in inflammatory responses and in the chemotaxis of leukocytes. Earlier work had suggested that lysine might function as a recognition molecule for SSAO/VAP-1. The present work reports the kinetics of the interaction of L-lysine and some of its derivatives with SSAO. Binding was shown to be saturable, time-dependent but reversible and to cause uncompetitive inhibition with respect to the amine substrate. It was also specific, since D-lysine, L-lysine ethyl ester and ε-acetyl-L-lysine, for example, did not bind to the enzyme. The lysinerich protein soluble elastin bound to the enzyme relatively tightly, which may have relevance to the reported roles of SSAO in maintaining the extra-cellular matrix (ECM) and in the maturation of elastin. Our data show that lysyl residues are not oxidized by SSAO, but they bind tightly to the enzyme in the presence of hydrogen peroxide. This suggests that binding in vivo of SSAO to lysyl residues in physiological targets might be regulated in the presence of H 2 O 2 , formed during the oxidation of a physiological SSAO substrate, yet to be identified.