obsolete alternative-complement-pathway C3/C5 convertase activity true (C3b)n,Bb (CVF)-dependent glycine-rich-beta-glucoprotein alternative-complement-pathway C3/C5 convertase activity heat-labile factor proenzyme factor B OBSOLETE. Catalysis of the cleavage of Arg-Ser bond in complement component C3 alpha-chain to yield C3a and C3b, and Arg bond in complement component C5 alpha-chain to yield C5a and C5b. C3 proactivator GO:0003812 CVF,Bb C3b,Bb,CVF,Bb,C5 convertase activity glycine-rich beta-glycoprotein C5 convertase activity C3 convertase activity properdin factor B activity molecular_function complement component C3/C5 convertase (alternative) activity complement C 3(C 5) convertase (amplification) cobra venom factor-dependent C3 convertase alternative complement pathway C3(C5) convertase activity complement factor B activity This term was made obsolete because it represents a gene product. serine-type endopeptidase activity