(1) Kininogens are inhibitors of thiol proteases, (2) HMW-kininogen plays an important role in blood coagulation by helping to position optimally prekallikrein and factor XI next to factor XII, (3) HMW-kininogen inhibits the thrombin- and plasmin-induced aggregation of thrombocytes, (4) the active peptide bradykinin that is released from HMW-kininogen shows a variety of physiological effects: (4A) influence in smooth muscle contraction, (4B) induction of hypotension, (4C) natriuresis and diuresis, (4D) decrease in blood glucose level, (4E) it is a mediator of inflammation and causes (4E1) increase in vascular permeability, (4E2) stimulation of nociceptors (4E3) release of other mediators of inflammation (e.g. prostaglandins), (4F) it has a cardioprotective effect (directly via bradykinin action, indirectly via endothelium-derived relaxing factor action), (5) LMW-kininogen inhibits the aggregation of thrombocytes, (6) LMW-kininogen is in contrast to HMW-kininogen not involved in blood clotting.
