Developer site: The content shown here is test data.

MyEClinic
MyEClinic
Health Dictionary AI Health Chat Find an Online Doctor
A serene Zen garden with raked sand and smooth stones, symbolising clarity and calm

Health Dictionary

Reliable, easy-to-read patient information on common medical conditions — written in plain language, free of jargon, and grounded in current evidence. Browse the most frequent diagnoses, understand what they mean for everyday life, and learn which steps and questions help you have a focused conversation with your doctor.

Back to skin conditions

Complement component 2

Introduction

Complement C2 is a protein that in humans is encoded by the C2 gene.[1] The protein encoded by this gene is part of the classical pathway of the complement system, acting as a multi-domain serine protease. Deficiency of C2 has been associated with certain autoimmune diseases.[1]

Function

Function

In the classical and lectin pathways of complement activation, formation of the C3-convertase and C5-convertases requires binding of C2 to an activated surface-bound C4b in the presence of Mg2+; the resultant C4bC2 complex is then cleaved by C1s or MASP2 into C2a and C2b. It is thought that cleavage of C2 by C1s, while bound to C4b, results in a conformational rotation of C2b whereas the released C2a fragment may retain most of its original structure.

C2b is the larger, enzymatically active fragment which is incorporated into the C3 convertase in this pathway, C4b2b (NB: some sources now refer to the larger fragment of C2 as C2b, making the C3 convertase C4b2b, whereas older sources refer to the larger fragment of C2 as C2a, making the C3 convertase C4b2a). The smaller fragment, C2a (or C2b, depending on the source) is released into the fluid phase.[2]

References

References

  1. ↑ 1.0 1.1 “Entrez Gene: C2 complement component 2”.
  2. ↑ Krishnan V, Xu Y, Macon K, Volanakis JE, Narayana SV (2009). “The structure of C2b, a fragment of complement component C2 produced during C3 convertase formation”. Acta Crystallographica D. 65 (Pt 3): 266–74. doi:10.1107/S0907444909000389. PMC 2651757. PMID 19237749.
Further reading

Further reading

External links