Complement and contact system serine proteases

The complement and contact system serine proteases are a functional group of enzymes that orchestrate the innate immune response and vascular regulation through highly regulated proteolytic cascades. The complement system utilizes proteases like C1r, C1s, and Factor D to mediate opsonization and cell lysis, while the contact system involves Factor XII and plasma kallikrein to generate bradykinin, a potent vasodilator [Source: UniProt, StatPearls]. Pathological overactivation or loss of endogenous regulation (e.g., C1-inhibitor deficiency) leads to life-threatening conditions such as hereditary angioedema (HAE) and atypical hemolytic uremic syndrome (aHUS) [Source: NIH]. Pharmacological intervention typically targets specific proteases to prevent the generation of pro-inflammatory peptides or the formation of the membrane attack complex. Modern therapeutics include monoclonal antibodies, small molecule inhibitors, and enzyme replacement therapies designed to restore balance to these complex systems [Source: PubMed PMID: 31558302].

Other names

Complement system proteasesContact system proteasesPlasma kallikrein-kinin system proteasesKKS proteases

Inhibition of specific serine proteases within the complement or contact cascades to prevent the formation of inflammatory mediators (like bradykinin or C5a) and the assembly of the membrane attack complex [Source: PubMed PMID: 32651006].