Tetanustoxin 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. Tetanustoxin Protein, Clostridium tetani, Recombinant (B2M & His) is expressed in E. coli expression system with N-6xHis-B2M tag. The predicted molecular weight is 66.3 kDa and the accession number is P04958.