Binding ability of Clostridium botulinum neurotoxin to the synaptosome upon treatment of various kinds of the enzymes

Abstract The binding ability of Cl. botulinum neurotoxin to synaptosomes upon treatment with various enzymes (neuraminidase, trypsin, and β-bungarotoxin containing phospholipase A 2 activity) was studied. When synaptosomes were treated with neuraminidase, their ability to bind toxin decreased; trypsin and β-bungarotoxin had slightly week or no effect. The decrease in toxin-binding ability of synaptosomes was paralleled by a release of sialic acid from the synaptosomes by the neuraminidase treatment. The toxin-binding ability of synaptosomes treated with neuraminidase was lower than untreated ones at a high concentration of sodium chloride. The binding of the toxin to synaptosomes occurred at least at the two types of structural sites, one site which contained sialic acid, and other site which was sensitive to high ionic strength. It may be possible that another binding state except these is present at the synapse.