Monoamine oxidase in adultAscaridia galli

Abstract

AbstractMonoamine oxidase (MAO), catalysing oxidative deamination of biogenic monoamines, has been detected in adultAscaridia galli. MAO was present in mitochondria and deaminated noradrenaline at the maximal rate, although serotonin, adrenaline, tyramine and dopamine were also degraded but more slowly. Of the organs studied, the body wall, female reproductive organ and intestine, the body wall (containing neuronal structures) showed highest MAO activity. Km value for chick ascarid mitochondrial MAO using tyramine as substrate was 1·66 x 10−3M and it was most active at 2·5 mm tyramine concentration, pH 7·5 and 40°C. MAO ofA. galliappeared to be thermolabile as nearly 80% of its activity was lost when the incubation temperature was increased 5° above optimum.