[A comparative analysis of monoamine oxidase activity in the tissues of the deep-sea squid (Berryteuthis magister) and the mouse under normal and elevated atmospheric pressure].

The monoamine oxidase (MAO) from the liver of Comandor squid inhabiting at depth of 800 m transformed histamine along with specific substrates (tyramine, serotonin, benzylamine). MAO from the squid nervous ganglia as well as from mouse liver and brain was inactive towards histamine. Under normal atmospheric pressure the activity of the enzyme prepared from the squid frozen tissues was an order of 10 lower than the enzymic activity revealed in fresh and previously frozen tissues of mouse brain and liver. Under 101 atm the squid tissue enzyme activity did not change whereas it decreased in mouse tissues. The distinctions in MAO sensitivity to high atmospheric pressure between land and deep-sea species is suggested to be due to both peculiar lipid composition of cell membranes and different structural features of the enzyme in the species investigated.