Formation of fluid-phase convertase C3

Stable Identifier
Gallus gallus
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In human, small amounts of hydrolyzed C3 (C3(H20) or C3i) are continuously formed in the fluid phase following spontaneous hydrolysis of the internal thioester bond of C3. C3i can bind to factor B which, in turn, is cleaved by factor D yielding an alternative fluid-phase C3 convertase, C3i:Bb.

Chicken factor B-like protease was shown to create a functional C3 convertase [Jensen LB & Koch C 1991]. Although an orthologue of human factor D has not been identified in the chicken genome, this chicken module describes a cleavage of factor B-like protease as an essential step of the chicken alternative complement pathway.

Literature References
PubMed ID Title Journal Year
6586103 Initiation of the alternative complement pathway due to spontaneous hydrolysis of the thioester of C3

Pangburn, MK, Muller-Eberhard, HJ

Ann N Y Acad Sci 1983
2060687 An assay for complement factor B in species at different levels of evolution

Jensen, LB, Koch, C

Dev. Comp. Immunol. 1991
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