A-B Toxin

∞ generated and posted on 2015.12.27 ∞

Category of exotoxins, named after their two-component protein nature.

A-B Toxins are intentionally produced by bacteria to modify host organisms, such as ourselves. They consistent two protein components or subunits, one that causes the effect, and the other which causes the exotoxin to be internalized by body cells so as to cause that effect.

A-B toxins consist of one component, or subunit, termed 'A', which is responsible for the toxic activity of the protein. The 'B' component, in turn, is responsible for cell targeting.

Basically 'B' binds to the surface a cell, the A-B toxin is endocytosed, and then the A component is freed to generate its toxic effect. As such, A-B toxins are described as type III exotoxins, which refers to their intracellular nature of their action.

Diphtheria and cholera, for example, are both caused by A-B toxins. The associated A-B toxins are known as diphtheria toxin and cholera toxin, respectively.