Definition: The larger fragment generated from the cleavage of COMPLEMENT C3 by C3 CONVERTASE. It is a constituent of the ALTERNATIVE PATHWAY C3 CONVERTASE (C3bBb), and COMPLEMENT C5 CONVERTASES in both the classical (C4b2a3b) and the alternative (C3bBb3b) pathway. C3b participates in IMMUNE ADHERENCE REACTION and enhances PHAGOCYTOSIS. It can be inactivated (iC3b) or cleaved by various proteases to yield fragments such as COMPLEMENT C3C; COMPLEMENT C3D; C3e; C3f; and C3g.
complement C3bBa complex [ C3bBa complex,complement 3b-associated factor B, fragment Ba,factor B-C3b fragment Ba ] Ba, MW 30-kDa; normally, Ba has low affinity for C3b; this C3bBa complex was prepared by the use of the cross-linking reagent dithiobis (succinimidyl propionate)
