Table 1

Characteristics of C1-Inh

Synonymsα2-neuramino-glycoprotein, C1-esterase inhibitor, C1s-inhibitor, C1-inactivator
ClassificationSerine proteinase inhibitor (serpin)
AbbreviationC1-Inh
Molecular weightNative glycosylated molecule, 104,000 to 105,000 (analytical ultracentrifugation and SDS-PAGE); protein backbone, 52,869 to 52,880 (478 amino acids according to complementary DNA sequencing)
SubstratesC1s, C1r, αFXIIa, βFXIIa, kallikrein, FXIa, plasmin, MASP-1, MASP-2
Half-life of clearance1-a 67 to 72 h
Concentration0.24 g/l (range 0.18–3.4) [∼2.3 μm]
Enzyme activityNone
Coenzymes/cofactorsGAG1-b

  • ↵1-a Determined in hereditary angioedema patients; half-life of clearance in other patients and in normal individuals is probably ∼28 h.

  • ↵1-b GAGs enhance inhibition of C1s, C1r, and FXIa but not that of FXIIa or kallikrein.