Cell surface:C4b Cell surface:C4b:C2a C3b iC3 C3 convertases C3 convertases spontaneously dissociate Authored: Jupe, S, 2010-10-26 C3b:Bb is naturally labile with a half-life of ~90 s. unless bound to properdin on the cell surface (Medicus et al. 1976). C4bC2a is also unstable, lasting at best a few minutes (Kerr et al. 1980). Decay is associated with the release of the Bb or C2a fragments respectively into the fluid phase. The liberated C3b/C4b is able to re-bind Bb/C2a if Factor B/C2 are present. Edited: Jupe, S, 2010-11-01 Pubmed6906228 Pubmed978134 Reactome Database ID Release 43981621 Reactome, http://www.reactome.org ReactomeREACT_118641 Reviewed: Bradley, DT, 2012-02-13 Reviewed: Fraczek, LA, 2012-02-13 has a Stoichiometric coefficient of 3 Properdin oligomer