C3a Human

Native human C3a is created by cleavage of human C3 protein by a human C3 convertase. C3a is a member of the anaphylatoxin family of three proteins (C3a, C4a and C5a) created by the activation of complement. C3a mediates various inflammatory responses including smooth muscle contraction, increased vascular permeability, vasodilation and release of histamine from mast cells and basophils. C3a (In contrast to C5a) does not exhibit significant neutrophil stimulating activities and does not induce chemotaxis, granule release or superoxide production. C3a acts through the C3a Receptor which is a G-protein coupled receptor found mainly on peripheral tissues, lymphoid cells and in the central nervous system. These activities of C3a are inactivated by removal of the C-terminal arginine which happens rapidly in plasma due to the action of carboxypeptidase N.