4a,5-Cycloaddiction reactions of acetylenic compounds at the flavoquinone nucleus as mechanisms of flavoprotein inhibitions.

4a,5-Cycloaddition at the flavoquinone, Mechanism of flavoprotein inhibitions Photochemically, covalent cycloaddition products of flavoquinone and acetylenic enzyme inhibitors have been prepared and elucidated, which appear analogous to flavoprotein-inhibitor complexes (monoamine and lactate oxidase). The additions occur with inhibitors of general type HC≡C-CH< at the C (4a) = N (5) azomethine grouping of oxidized flavin. The spectral properties of adducts and their chemical reactivity is described.