Kinetics and stereospecificity of the lysyl oxidase reaction

• Published in: The Journal of biological chemistry 1993-06, Vol.268 (16), p.11573-11579
• Main Authors: SHAH, M. A, SCAMAN, C. H, PALCIC, M. M, KAGAN, H. M
• Format: Article
• Language: English
• Subjects: Amines - metabolism; Analytical, structural and metabolic biochemistry; Animals; Aorta - enzymology; Biological and medical sciences; Cattle; Deuterium; Electrophoresis, Polyacrylamide Gel; Enzymes and enzyme inhibitors; Fundamental and applied biological sciences. Psychology; Hydrogen; Magnetic Resonance Spectroscopy; Muscle, Smooth, Vascular - enzymology; Oxidoreductases; Protein-Lysine 6-Oxidase - isolation & purification; Protein-Lysine 6-Oxidase - metabolism; Stereoisomerism; Substrate Specificity; Tyramine - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/s0021-9258(19)50239-3

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.