Skip to main content
. Author manuscript; available in PMC: 2010 Sep 1.
Published in final edited form as: Mol Immunol. 2009 Aug 5;46(15):2902–2910. doi: 10.1016/j.molimm.2009.07.006

Table 2.

Decay acceleration of C3/C5 convertases by C4BP

Enzyme IC50a (nM)
Lectin pathway C3/C5 convertases
 Soluble C3 convertase (C4b,C2a) NDb
 Surface-bound C3 convertase (ZymM1,C4b,C2a) 0.54 ± 0.19
 Surface-bound C3 convertase (EManM1,C4b,C2a) 1.03 ± 1.00
 High affinity C5 convertase (ZymM1,C3bC4b,C2a) 0.81 ± 0.11
 High affinity C5 convertase (EManM1,C3bC4b,C2a) 3.47 ± 2.15
Classical pathway C3/C5 convertasesc
 Soluble C3 convertase (C4b,C2a) 17 ± 6
 Surface bound C3 convertase (EAC1,C4b,C2a) 11 ± 8
 High Affinity C5 convertase (EAC1,C3bC4b,C2a) 20 ± 11
a

IC50, C4BP concentration required to accelerate the decay of C3 convertase and C5 convertase by 50% as described in Materials and Methods. The lectin pathway C3 convertase was assembled on zymosan and EMan cells bearing 20,000-431,000 C4b/Zym and 23,000-189,000 C4b/EMan. The lectin pathway C5 convertase was assembled on zymosan bearing 11,000-25,000 C4b/Zym and 450,000 C4b/EMan. Values are mean ± S.D. (n = 3).

b

ND, not determined.

c

IC50 for classical pathway C3 convertase that was assembled on EA bearing 60,000 C4b/EA and the C5 convertase assembled on EA bearing 11,200 C4b/EA have been reported previously (Rawal et al., 2007).