Steric influence on inhibition of monoamine oxidase forms by 2,3-dichloro-alpha-methylbenzylamine.

The (+) isomer of 2,3-dichloro-alpha-methylbenzylamine inhibited the oxidation of serotonin (a substrate of type A MAO) by rat brain mitochondrial monoamine oxidase (MAO) more effectively than it inhibited the oxidation of phenylethylamine (a substrate for type B MAO). In contrast, the (-) isomer inhibited phenylethylamine oxidation more than it inhibited serotonin oxidation. These apparently are the first pair of stereoisomers observed to have opposite selectivity as inhibitors of types A and B MAO.