Monoamine oxidase activity in<i>Paracentrotus lividus</i>sperm cells

Abstract

Monoamine oxidase activity has been studied in mitochondria isolated from Paracentrotus lividus sperm cells using 5-hydroxytryptamine, tyramine and phenylethylamine as substrates. Under our experimental conditions phenylethylamine was the most actively deaminated substrate; the highest activities were found at pH 7.6 with phenylethylamine, while with 5-hydroxytryptamine and tyramine they reached a maximum at pH 8.9. Regardless of the substrate used, deprenyl inhibited the enzyme activity to a greater extent than clorgyline. This research was undertaken in order to investigate the possible role of a monoaminergic system in sea urchin sperm physiology.