Species-specific differences in the substrate-inhibitory specificity of cholinesterases from optical ganglia of squids of the Gonatidae family

A comparative study was carried out of the substrate and inhibitory specificity of cholinesterase preparations from squids, representatives of 3 genes and 5 species of the Gonatidae family:Berryteuthis (B. magister andB. anonichos),Gonatus (G. kamtschaticus andG. tinro), andGonatipsis (G. borealis), that have overlapping habitation areals in the Bering Sea. As substrates, there were used bromides of acetylthiocholine, propionylthiocholine, and butyrylthiocholine, as organophosphorus inhibitors, diisopropylfluorophosphate, a cation-containing inhibitor, and 4 hydrophobic compounds. The homogeneity of the cholinesterase activity in these preparations has been shown, the intergenus and interspecies differences in the enzyme properties are revealed, and also the peculiarity of properties of enzymes from Gonatidae squids is emphasized in comparison with cholinesterase from the Pacific squidTodarodes paciflcus and “standard” mammalian enzymes (from human erythrocytes and horse blood serum). The revealed interspecies differences are discussed in terms of evolutionary development of the Gonatidae family.