[A factor from the venom of the Central Asiatic cobra Naja naja oxiana, which inactivates component C4 of human complement].
An acid glycoprotein (mol. m. 60 kDa) containing 6 sialic acid residues and N-terminal Thr was isolated from the venom of the central asian cobra Naja naja oxiana. The protein has an anticomplementary activity selectively inactivating of the C4 component of the human complement. This factor (CFA-Ib) binds C4 with Ki = 0.27 +/- 0.13 microM and then irreversible inactivates it with a rate constant k = 0.75 +/- 0.25 min-1. Membrane bound C4b restores its ability of CFA-Ib binding. This binding hinders component C2 sorption on C4b and C3 convertase formation.
L V
LV
Kozlov
B B
BB
Shoĭbonov
D050577:Complement C3-C5 Convertases / Q000302:isolation & purification; D003181:Complement C4 / Q000037:antagonists & inhibitors*; D015935:Complement C4b; D004546:Elapid Venoms / Q000032:analysis*; D006023:Glycoproteins / Q000302:isolation & purification*; D006801:Humans; D010446:Peptide Fragments
D003181:Complement C4; D004546:Elapid Venoms; D006023:Glycoproteins; D010446:Peptide Fragments; C033860:complement C4c; D015935:Complement C4b; D050577:Complement C3-C5 Convertases
Faktor iada sredneaziatskoĭ kobry Naja naja oxiana inaktiviruiushchiĭ komponent C4 komplementa cheloveka.