Factor I, Human, Protein, Each

Details

Native factor I from human serum. Glycoprotein composed of two non-identical disulfide-bonded subunits of M.W. of 50kDa (α) and 38kDa (β). Present in normal human serum at about 34μg/mL. A serine protease that requires protein cofactor in order to effect substrate cleavage. Thus, either Factor H or Factor I mediates cleavage of C3b. C4-binding protein or complement receptor CR1 can function as the cofactor required for Factor I-mediated cleavage of C4b.