Plasma prekallikrein is a glycoprotein that participates in the surface-dependent activation of blood coagulation, fibrinolysis, kinin generation and inflammation.
The heavy chain originates from the amino-terminal end of the zymogen and contains 4 tandem repeats of 90 or 91 amino acids.
The heavy chain is required for the surface-dependent pro-coagulant activity of plasma kallikrein.
The light chain contains the active site or catalytic domain of the enzyme and is homologous to the trypsin family of serine proteases.
Plasma prekallikrein deficiency causes a prolonged activated partial thromboplastin time in patients.