Some Aspects of the Oxidative Deamination of Tryptamine by MAO-A and MAO-B in Different Tissues

Tryptamine has been found in mammalian brain (Philips et al., 1974); it possesses a high turnover rate (Durden and Philips, 1980). Oxidative deamination catalyzed by monoamine oxidase is its major catabolic pathway (Weissback et al., 1961; Wu and Boulton, 1973). It was, at first, reported to be oxidized solely by MAO-B (Houslay and Tipton, 1974), then by both MAO-A and MAO-B (White and Tansik, 1979) but most recently predominantly by MAO-A in the human (Bieck et al., 1984). This present study was attempted in order to try to understand how MAO-A and MAO-B are involved in the deamination of tryptamine. Mitochondrial MAO-A and MAO-B was prepared from different tissues; a kinetic analysis on the deamination of tryptamine was then carried out.