Redox regulation of botulinum neurotoxin toxicity: therapeutic implications.

Botulinum neurotoxin causes botulism, and the only effective antidote is the antitoxin. Botulinum neurotoxins are disulfide linked di-chain proteins encompassing a light chain Zn2+-protease that is translocated by a heavy chain channel from the synaptic vesicle lumen into the neuronal cytosol where it acts. Protease release from the channel is required for toxicity. The Thioredoxin Reductase-Thioredoxin system cleaves the interchain disulfide, and its inhibition prevents neurotoxicity, and may provide novel strategies for chemoprophylaxis and therapy.