Prekallikrein

Prekallikrein (PK) deficient plasma from 5-Diagnostics for contact activation pathway research and kallikrein-kinin system studies. Prekallikrein circulates in plasma as a zymogen in a non-covalent complex with high-molecular-weight kininogen (HMWK) — upon surface contact activation, Factor XIIa converts prekallikrein to the active serine protease plasma kallikrein, which amplifies further Factor XII activation in a reciprocal feedback loop and generates bradykinin from kininogen.

Prekallikrein deficiency produces a prolonged APTT in vitro without associated clinical bleeding — the PK-deficient APTT corrects on prolonged incubation with the APTT reagent (the Passovoy effect), distinguishing it from deficiencies of other contact factors. This characteristic makes prekallikrein deficient plasma an important control in APTT-based assay development and contact activation pathway studies.

5-Diagnostics prekallikrein deficient plasma is produced by immunodepletion of PK from large-pool human citrated plasma, with residual prekallikrein confirmed below 1% of normal. Used in research characterizing the contact activation pathway in thrombosis, sepsis-coagulopathy models, and therapeutic target validation studies for kallikrein inhibitors and Factor XII inhibitors under development. For Research Use Only. Not for use in diagnostic procedures.