. "Authored: Jupe, S, 2010-10-26"^^ . "Edited: Jupe, S, 2010-11-01"^^ . "Reviewed: Fraczek, LA, 2012-02-13"^^ . "Reviewed: Bradley, DT, 2012-02-13"^^ . "Factor I cleaves the truncated alpha (a') chain of C4b between Arg-1336 and Asn-1337 and then again between Arg-956 and Thr-957, producing a 16 kDa fragment known as alpha4, derived from the C terminus of the a' chain, followed by a 27 kDa alpha3 fragment. The remaining alpha 2 (C4d) fragment stays covalently bound to the cell membrane while the complex of disulfide-linked alpha3, alpha4, beta chain and gamma chain are released (C4c) into the fluid phase (Fujita et al. 1978)."^^ . . . . . . . . . . "Factor I inactivates MCP/CR1-bound C4b/C3b"^^ . "3.4.21"^^ . . . . . . . . .