[The crucial component of the complement pathway-C3].
D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D003167:Complement Activation; D003176:Complement C3 / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D003179:Complement C3b / Q000502:physiology; D006801:Humans
D003176:Complement C3; D003179:Complement C3b