title: Kinetics and stereospecificity of the lysyl oxidase reaction.
abstract: The structural specificity of amine oxidation by lysyl oxidase was investigated using kinetic and NMR spectroscopic analyses. Substrate efficiency increased with increasing molecular distance from the alpha-carbon of the aromatic moiety substituted on the aliphatic chains of a series of primary amines. The p-hydroxyl substituent of p-hydroxybenzylamine significantly increased kcat over that of benzylamine, whereas this was not the case when tyramine and phenethylamine were compared. Direct spectrophotometric measurement of p-hydroxybenzaldehyde formation yielded burst kinetics, the second, slower phase of which was eliminated under anaerobic conditions. Thus, enzyme reoxidation is the more rate-limiting of the two half-reactions catalyzed with this substrate by this ping-pong enzyme. 1H NMR spectroscopy of the alcohol reductively derived from the aldehyde product of the lysyl oxidase-catalyzed oxidation of deuterated tyramine indicated that the pro-S but not the pro-R alpha-deuteron was catalytically abstracted. Moreover, lysyl oxidase catalyzed solvent exchange of protons at the C-2 position. Such stereospecificity and proton exchange uniquely differentiates lysyl oxidase from all but an aortic semicarbazide-sensitive amine oxidase among the pro-S-specific copper-dependent amine oxidases analyzed thus far.
authors.affiliation: Department of Biochemistry, Boston University School of Medicine, Massachusetts 02118.
authors.forename: M A
authors.initials: MA
authors.lastname: Shah
authors.forename: C H
authors.initials: CH
authors.lastname: Scaman
authors.forename: M M
authors.initials: MM
authors.lastname: Palcic
authors.forename: H M
authors.initials: HM
authors.lastname: Kagan
mesh_terms: D000588:Amines / Q000378:metabolism; D000818:Animals; D001011:Aorta / Q000201:enzymology; D002417:Cattle; D003903:Deuterium; D004591:Electrophoresis, Polyacrylamide Gel; D006859:Hydrogen; D009682:Magnetic Resonance Spectroscopy; D009131:Muscle, Smooth, Vascular / Q000201:enzymology; D008249:Protein-Lysine 6-Oxidase / Q000302:isolation & purification / Q000378:metabolism*; D013237:Stereoisomerism; D013379:Substrate Specificity; D014439:Tyramine / Q000378:metabolism
chemical_list: D000588:Amines; D006859:Hydrogen; D003903:Deuterium; D008249:Protein-Lysine 6-Oxidase; D014439:Tyramine