Complement C5 is activated by C5 convertase, inducing C5-C9 assembly to form the membrane attack complex. The transient C6 binding site on C5b is critical for the formation of the cleavage complex. Complement C5a Protein, Cynomolgus is the recombinant cynomolgus-derived Complement C5/C5a protein, expressed by E. coli , with tag free.