Purification of factor XII (Hageman factor) from human plasma

The contact system in human malignant and benign ascites

The plasma contact system was studied in ascites and plasma from patients with gastrointestinal cancer and patients with liver failure. Our study demonstrates the presence of factor XII, factor XI, and prekallikrein and their main inhibitors in ascites and plasma from both patient groups. Both factor XII-like and plasma kallikrein-like activities were detected in the malignant ascites. The kallikrein-like activity in malignant ascites was found in complex with alpha 2-macroglobulin. In plasma samples from the patients functional values of factor XII and prekallikrein were decreased compared to controls. In benign ascites the proenzyme levels were significantly lower than in malignant ascites. Functional inhibition values in ascites and plasma from patients were unexpectedly high. Our findings indicate that the plasma contact system is activated in the ascites from cancer patients. Activation of the contact system generates vasoactive mediators, which may play a role in the accumulation of malignant ascites.

Purification of human factor XII from plasma using zinc chelate affinity chromatography

Human factor XII (Hageman Factor) was isolated from human plasma to apparent homogeneity using a four step procedure with yields up to 30%. The method, which is more rapid than the current conventional procedures, consists of a 25-50% ammonium sulfate fractionation, two affinity chromatography steps using Zinc Chelate Sepharose, followed by gel filtration. The isolated zymogen factor XII was a single protein component when examined by SDS PAGE with a Mr of 80,000. Activation of zymogen factor XII to its active enzymatic forms by kallikrein resulted in factor XIIa and factor XIIf as observed with factor XII purified by other procedures.

Preparation of beta-XIIa (Hageman factor fragment) from human plasma

beta-Factor XIIa (beta-XIIa, Mr approximately 30,000) was isolated from human plasma by a procedure which utilized, as an initial step, the adsorption of Factor XII to celite. Activation of Factor XII and subsequent release of beta-XIIa was brought about by the proteolytic action of co-adsorbed kallikrein. Two successive chromatographic procedures were then used to achieve a final purification of 4,420-fold over plasma and an overall field of 2.3 mg of beta-XIIa per liter.

Purification and studies of components of the haemostatic system by affinity chromatography

The application of affinity chromatographic techniques for separations and studies on molecular interactions of the components of the blood coagulation system is reviewed. Most of the components have been purified using processes involving one or several affinity chromatographic steps. Many different kinds of affinity chromatography have been used, including inhibitor interaction chromatography, effector interaction chromatography, immunosorption, hydrophobic interaction chromatography, metal chelate chromatography and covalent chromatography. Affinity chromatographic techniques have also been used to study molecular interactions such as the fibrin polymerization process. One example of large-scale purification of a clinically used component is given.

Surface activation of factor XII (Hageman factor)--critical role of high molecular weight kininogen and another potentiator)

When factor XII was adsorbed to kaolin it slowly became activated and converted prekallikrein to kallikrein. In the presence of HMW-kininogen the rate of activation of factor XII and consequently that of prekallikrein was markedly enhanced. The enhancing effect of HMW-kininogen was a dose-dependent phenomenon. In order to enhance the activation of factor XII on a surface the HMW-kininogen molecule had to be intact. Cleavage of HMW-kininogen by kallikrein decreased the enhancing effect of HMW-kininogen, there being an inverse relation between the bradykinin-generated and the capacity to enhance factor XII activation. Another 'potentiator' of factor XII activation was isolated from proteins adsorbed to aluminum hydroxide. This potentiator further increased the activation of factor XII, also in a dose-dependent fashion. It was postulated that factor XII is slowly converted into its active form by exposure to negatively charged surfaces; that this process is enhanced by kallikrein and further accelerated by HMW-kininogen and the 'potentiator'; and that these enhancing substances probably act by opening active sites on the factor XII molecule.

Isolation and characterization of bovine factor XII (Hageman factor)

Factor XII was purified approximately 14 000-fold from bovine plasma by ammonium sulfate fractionation followed by heparin-agarose, DEAE-Sephadex, CM-cellulose, arginine-agarose, and benzamidine-agarose column chromatography. By this method, about 15 mg of protein was purified from 15 L of plasma with an overall yield of 18%. The purified protein was homogeneous as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and amino-terminal analysis. Bovine factor XII is a glycoprotein with a mol wt of 74 000 as determined by sedimentation equilibrium centrifugation. It contains 13.5% carbohydrate including 3.4% hexose, 4.7% N-acetylhexosamine, and 5.4% N-acetylneuraminic acid. Factor XII is a single polypeptide chain with an NH2-terminal sequence of Thr-Pro-Pro-Trp-Lys-Gly-Pro-?-Lys-His. This sequence is homologous to the reactive-site regions of a number of protease inhibitors. The amino acid sequence of a carboxyl-terminal fragments prepared by cyanogen bromide digestion was found to be Leu-Cys-Ala-Gly-Phe-Leu-Glu-Gly-Gly-Thr-Asp-Ala-Cys-Gln-Gly-Asp-SER-Gly-Gly-Pro-Leu-Val-Cys-Glu-Asp-Glu. This sequence is homologous with the active site of a number of plasma serine proteases including thrombin, factor IXa, factor Xa, and plasmin. These data indicate that bovine factor XII is a precursor to a serine enzyme with an inhibitor sequence and a catalytic site located in the same single polypeptide chain.