2643 Tetanus toxin Tetanus toxin is a neurotoxin produced by Clostridium tetani. Tetanus toxin is an A-B toxin. It is composed of a 100 kDa heavy chain (fragment B) and a 50kDa light chain (fragment A), which remain connected by a disulfide bridge. Tetanus toxin is one of the three most poisonous substances known to humans, the other two being the toxins of botulism and diphtheria. (L1738) 676570-37-9 150680.98000000068 Clear solution. >10 mg/mL Ingestion (L1816) ; inhalation (L1816) ; dermal (L1816) The bacterium synthesizes the tetanus toxin as a single 150kDa polypeptide chain (called the progenitor toxin), that is cleaved extracellularly by a bacterial protease into a 100 kDa heavy chain (fragment B) and a 50kDa light chain (fragment A), which remain connected by a disulfide bridge. The toxin acts at several sites within the central nervous system, including peripheral nerve terminals, the spinal cord, and brain, and within the sympathetic nervous system. The toxin is taken up into within the nerve axon and transported across synaptic junctions, until it reaches the central nervous system, where it is rapidly fixed to gangliosides at the presynaptic junctions of inhibitory motor nerve endings. Here it blocks inhibitory impulses by interfering with the release of neurotransmitters, including glycine and gamma-aminobutyric acid. Tetanus toxin appears to prevent the release of neurotransmitters by selectively cleaving a component of synaptic vesicles called synaptobrevin II. This leads to unopposed muscle contraction and spasm. (L1738) Free toxin may be removed by opsonization via the reticuloendothelial system (primarily the liver and kidneys) or it may be degraded through cellular internalization via the lysosomes. Lysosomes are membrane-enclosed organelles that contain an array of digestive enzymes, including several proteases. 1 ng/mg for mice. (A2855) No indication of carcinogenicity to humans (not listed by IARC). Tetanus toxin is a neurotoxin produced by Clostridium tetani. (L1738) Tetanus toxin is a neurotoxin that causes tetanus. (L1738) Symptoms of tetanus include unopposed muscle contraction and spasm, Risus Sardonicus (a rigid smile), Trismus (commonly known as lock-jaw), and Opisthotonus (rigid, arched back). Seizures may occur, and the autonomic nervous system may also be affected. (L1738) 2009-07-06T18:11:28Z 2014-12-24T20:25:45Z P04958 Tetanus toxin 1A8D true Exogenous Liquid 1a8d_bio_r_500.jpg image/jpeg 39744 2014-10-14T18:13:34Z BSEQ0002801