MODELING OF QUINOPROTEIN FUNCTIONS

The model compound of TTQ (tryptophan tryptophylquinone), the active s ite cofactor of bacterial methylamine dehydrogenases, was synthesized for the first time. H-1 NMR analysis and theoretical calculations on t he model compound (1) indicate that its molecular geometry is close to that of TTQ in the enzyme active site. The redox potential and spectr al characteristics (UV-vis and resonance Raman) of 1 were also very si milar to those of the native enzymes. Model compound 1 catalyzes the o xidation of benzylamine in CH3OH, indicating that it possesses the sam e chemical functions as methylamine dehydrogenases. Product analysis o n the reactions of 1 with several amines indicate that the amine oxida tion proceeds via a transamination mechanism. In order to study struct ure-reactivity relationships of TTQ, 4-substituted-6,7-indolequinones were also synthesized and their physicochemical properties and catalyt ic activity in the amine oxidation were compared to those of model com pound 1.