C2/Complement C2 protein is essential in the classical pathway of the complement system. Activated by factor C1, C2 is cleaved into C2b and C2a. As a serine protease, C2a interacts with C4b, generating the C3 or C5 convertase. This crucial process activates and amplifies the complement cascade. C2/Complement C2 Protein, Human (HEK293, His) is the recombinant human-derived C2/Complement C2 protein, expressed by HEK293 , with C-His labeled tag.