And that's why we call this a cascade of events. In fact, the complement system is also sometimes known as the complement cascade system because we have so many events taking place and so many proteins are being activated. So let's see exactly how the C Five is activated. Basically, the C three B binds onto the allosteric side and C Five creating a conformational change in its structure. And then the C four B C two B complex goes on and cleaves the C five to form the C five A and C five B Now, C five A doesn't only act as an anaphyla toxin and stimulates the release of histamine. But the C five A also acts in a process known as chemotaxis.