Tetanolysin is a

toxin A toxin is a naturally occurring organic poison produced by metabolic activities of living cells or organisms. Toxins occur especially as a protein or conjugated protein. The term toxin was first used by organic chemist Ludwig Brieger (1849– ...

produced by ''

Clostridium tetani ''Clostridium tetani'' is a common soil bacterium and the causative agent of tetanus. Vegetative cells of ''Clostridium tetani'' are usually rod-shaped and up to 2.5 μm long, but they become enlarged and tennis racket- or drumstick-shaped when ...

'' bacteria. Its function is unknown, but it is believed to contribute to the

pathogenesis Pathogenesis is the process by which a disease or disorder develops. It can include factors which contribute not only to the onset of the disease or disorder, but also to its progression and maintenance. The word comes from Greek πάθος ''pat ...

tetanus Tetanus, also known as lockjaw, is a bacterial infection caused by ''Clostridium tetani'', and is characterized by muscle spasms. In the most common type, the spasms begin in the jaw and then progress to the rest of the body. Each spasm usually ...

. The other ''C. tetani'' toxin,

tetanospasmin Tetanus toxin (TeNT) is an extremely potent neurotoxin produced by the vegetative cell of ''Clostridium tetani'' in anaerobic conditions, causing tetanus. It has no known function for clostridia in the soil environment where they are normally ...

, is more definitively linked to tetanus. It is sensitive to oxygen. Tetanolysin belongs to a family of protein toxins known as

thiol-activated cytolysin The thiol-activated Cholesterol-dependent Cytolysin (CDC) familyTC# 1.C.12 is a member of the MACPF superfamily. Cholesterol dependent cytolysins are a family of β-barrel pore-forming exotoxins that are secreted by gram-positive bacteria. CDCs ...

s, which bind to

cholesterol Cholesterol is any of a class of certain organic molecules called lipids. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell mem ...

. It is related to

streptolysin Streptolysins are two hemolytic exotoxins from ''Streptococcus''. Types include streptolysin O (SLO; ''slo''), which is oxygen-labile, and streptolysin S (SLS; ''sagA''), which is oxygen-stable. SLO is part of the thiol-activated cytolysin fami ...

O and the θ-toxin of ''

Clostridium perfringens ''Clostridium perfringens'' (formerly known as ''C. welchii'', or ''Bacillus welchii'') is a Gram-positive, rod-shaped, anaerobic, spore-forming pathogenic bacterium of the genus '' Clostridium''. ''C. perfringens'' is ever-present in nature an ...

''. Cytolysins form pores in the

cytoplasmic membrane The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment ( ...

that allows for the passage of

ion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

s and other molecules into the cell. The molecular weight of tetanolysin is around 55,000 daltons.Tetanolysin
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References

Further reading