The two arms of the<unk>  system. PKa's cleavage of HK liberates BK and promotes inflammation. FXIIa's cleavage of FXI initiates coagulation. In the<unk>  or CAS, three proteins in the blood, factor XII (FXII), prekallikrein (PK) and high molecular weight kininogen (HK), bind to a surface and cause blood coagulation and inflammation. FXII and PK are proteases and HK is a non-enzymatic co-factor. The CAS can activate the kinin–kallikrein system and blood coagulation through its ability to activate multiple downstream proteins. The CAS is initiated when FXII binds to a surface and reciprocal<unk>  of FXII and PK occurs, forming FXIIa and PKa. FXIIa can initiate the coagulation cascade by cleaving and<unk> g factor XI (FXI), which leads to formation of a blood clot. Additionally, the CAS can activate the kinin–kallikrein system when PKa cleaves HK to form cHK, releasing a peptide known as bradykinin (BK). BK and its derivatives bind to bradykinin receptors B1 and B2 to mediate inflammation.
Contact activation system
Respirometer
Spirometer
Rapid response system
Allergy test
Breath diagnostics
Respiratory pressure meter
Skin allergy test