The use of mechanism-based inactivators to probe the mechanism of monoamine oxidase.

MAO, and analysed the resulting enzyme activity obtained. The transfected cells expressed monoamine oxidase activity of the correct form showing that a single subunit is sufficient to generate activity and that the identified cDNAs code for enzymically active type A and type B monoamine oxidases. The successful expression of the monoamine oxidase cDNAs in a mammalian cell enables the direct study of hypotheses of structure and function. The production of chimaeric forms of monoamine oxidase consisting of the N-terminal sequences of MAO-A and the C-terminal sequences of MAO-B, for example, could be illuminating. When these constructs are transfected into mammalian cells enzymic assays may reveal which domains of the MAOs determine the enzyme specificity. More specific site-directed mutation of individual amino acid residues will identify those amino acids forming the active site.