Partial purification of α-glycerotoxin, a presynaptic neurotoxin from the venom glands of the polychaete annelid glycera convoluta

The venom secreted from glands appended to the jaws of Glycera convoluta , a Polychaete Annelid, increases the spontaneous quantal release of transmitter from nerve terminals. The component that is biologically active on vertebrate cholinergic nerve terminals has recently been shown to be a high molecular weight protein. In the present work, the crude extract from the venom apparatus was shown to be toxic for mammals and crustaceans. It was fractionated by gel filtrations and ion exchange chromatographies. The biologically active component at frog neuromuscular junctions, α-glycerotoxin, was purified more than 1,000-fold. It is distinct from the components that are toxic for crustaceans. Purified α-glycerotoxin is a globular protein of 300,000 ± 20,000 mol wt. It has a Stokes radius of 65 A and a sedimentation coefficient of 11 S. By its molecular properties, α-glycerotoxin appears distinct from other neurotoxins such as α-latrotoxin, which also trigger transmitter release.