title: Identification of prekallikrein and high-molecular-weight kininogen as a complex in human plasma.
abstract: Prekallikrein and high-molecular-weight kininogen were found associated in normal human plasma at a molecular weight of 285,000 as assessed by gel filtration on Sephadex G-200. The molecular weight of prekallikrein in plasma that is deficient in high-molecular-weight kininogen was 115,000. This prekallikrein could be isolated at a molecular weight of 285,000 after plasma deficient in high-molecular-weight kininogen was combined with plasma that is congenitally deficient in prekallikrein. Addition of purified 125I-labeled prekallikrein and high-molecular-weight kininogen to the respective deficient plasma yielded a shift in the molecular weight of prekallikrein, and complex formation could be demonstrated by incubating prekallikrein with high-molecular weight kininogen. This study demonstrates that prekallikrein and high-molecular-weight kininogen are physically associated in plasma as a noncovalently linked complex and may therefore be adsorbed together during surface activation of Hageman factor. The complex is disrupted when these proteins are isolated by ion exchange chromatography.
mesh_terms: D005174:Factor XII / Q000378:metabolism; D006801:Humans; D007610:Kallikreins / Q000378:metabolism*; D007704:Kininogens / Q000097:blood* / Q000378:metabolism; D008970:Molecular Weight; D011288:Prekallikrein / Q000378:metabolism*; D011485:Protein Binding
chemical_list: D007704:Kininogens; D005174:Factor XII; D011288:Prekallikrein; D007610:Kallikreins