Purity > 90% as determined by SDS-PAGE. MW: 55.4kDa. Partial: 123-573aa. N-terminal 6xHis-tagged. Clostridium tetani (strain Massachusetts / E88). Tetanus toxin acts by inhibiting neurotransmitter release. It binds to peripheral neuronal synapses, is internalized and moves by retrograde transport up the axon into the spinal cord where it can move between postsynaptic and presynaptic neurons. It inhibits neurotransmitter release by acting as a zinc endopeptidase that catalyzes the hydrolysis of the '76-Gln-|-Phe-77' bond of synaptobrevin-2.