Do MAO A and MAO B utilize the same mechanism for the C-H bond cleavage step in catalysis? Evidence suggesting differing mechanisms

• Type of Material: Article
• Authors: R. Orru, Emory University; M. Aldeco, Emory University; Dale E Edmondson, Emory University
• Language: English
• Date: 2013-06
• Publisher: Springer Verlag (Germany)
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: Springer-Verlag Wien 2013
• Final Published Version (URL): http://link.springer.com/article/10.1007%2Fs00702-013-0991-3
• Title of Journal or Parent Work: Journal of Neural Transmission
• ISSN: 0300-9564
• Volume: 120
• Issue: 6
• Start Page: 847
• End Page: 851
• Grant/Funding Information: This work was supported by a grant from the National Institutes of Health (GM29433).
• Keywords: mechanistic properties; monoamine oxidase B; monoamine oxidase A; human
• Research Categories: Biology, Neuroscience; Chemistry, Biochemistry; Health Sciences, General

Abstract

Summary The detailed molecular mechanism proposed for the MAO-catalyzed oxidation of amines has been controversial with the basic assumption that both MAO A and MAO B follow the same pathway for the C-H bond cleavage step. Using the mechanistic approach of investigation of electronic effects of various benzylamine ring substituents in experiments at pH=9.0, human MAO A exhibits a kinetic behavior characteristic of a H+ abstraction while human MAO B exhibits kinetic properties characteristic of a H− abstraction. These results lead to the conclusion that the assumption that MAO A and MAO B follow identical mechanisms is incorrect.