https://slavyanski.net/sb2020/story.php?title=system-comprises-four-plasma-proteins-circulating-as-zymogens-in-the-bloodstream-8 System comprises four plasma proteins, circulating as zymogens in the bloodstream or being assembled on various cell types: the serine proteases factor XII (FXII), factor XI (FXI), and prekallikrein (PKK) and the nonenzymatic cofactor high-molecularweight kininogen (HK). The latter forms equimolar complexes with plasma kallikrein (PK) or FXI. The cascade is initiated upon contact to a negatively c Thu, 06 Aug 2020 07:59:01 UTC en