C2 deficiency

Gene Information


HUGO name: C2


  • Complement component 2
  • Complement C2 precursor(C3/C5 convertase)


Reference sequences

Chromosomal location


Protein Information


Protein function:

Component C2 which is part of the classical pathway of the complement system is cleaved by activated factor C1 into two fragments: C2b and C2a. C2a, a serine protease, then combines with complement factor 4b to generate the C3 or C5 convertase.

Catalytic activity:

Cleaves C3 in the alpha-chain to yield C3a and C3b. Cleaves C5 in the alpha-chain to yield C5a and C5b. Both cleavages take place at the C-terminal of an Arginine residue.


C2 is a Major Histocompatibility Complex Class-III protein.


Expression pattern for human

Tissue Expression (%) Clones
eye, cornea 30.15 2:451
skin, melanocyte 13.07 1:520
blood, white cells 7.47 1:910
sympathetic trunk 7.45 1:913
dorsal root ganglia 6.66 1:1021
hepatocellular carcinoma 5.73 12:14226
lung with fibrosis 4.60 1:1479
uterus, endometrium 3.80 1:1790
uterus, pooled 2.19 5:15533
brain, pooled 2.15 1:3166