4-DIMETHYLAMINOPHENETHYLAMINE, A SENSITIVE, SPECIFIC, ELECTROCHEMICALLY DETECTABLE MONOAMINE OXIDASE-B SUBSTRATE

4-Dimethylaminophenethylamine (DMAPEA) was characterized as an MAO sub strate. This compound was unaffected by MAO-A, while its oxidation by MAO-B was linear as a function of both time and enzyme concentration, with Km = 5.8 mu M and Vmax = 21.2 pmol/min/mg protein, using a crude rat brain mitochondrial suspension as source of MAO. Both DMAPEA and i ts oxidation product, 4-dimethylaminophenylacetic acid (DMAPAA), can b e detected electrochemically at 0.85 V. The high MAO-B affinity and se lectivity of DMAPEA, together with its low oxidation potential, make t his molecule a unique tool to determine MAO-B activity in a wide varie ty of tissue preparations using HPLC-ED.