Purification and characterization of multiple forms of human plasma prekallikrein

Interactions of antithrombin and proteins in the plasma contact activation system with immobilized functional heparin

The interactions of antithrombin (AT) and the contact phase clotting factors with two commercially available heparinized surfaces are reported. The Carmeda (CBAS) and Corline surfaces along with controls (a sulfonated polyethylene surface and a CBAS analog in which the heparin used was devoid of specific AT-binding sequences) were exposed to human plasma. Adsorbed proteins were eluted and examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. The CBAS and Corline surfaces adsorbed large amounts of AT, whereas adsorption on the controls was negligible. Immunoblots for the four contact phase clotting factors indicated less contact activation on the CBAS and Corline surfaces than on the controls. Determination of adsorbed functional AT using a FXa inhibition assay showed that the CBAS surface adsorbed about 4 times as much AT as the Corline surface. Adsorption of AT to the control surfaces was minimal. Assays for adsorbed FXII and FXIIa based on kallikrein generation showed that all four surfaces adsorbed similar amounts of FXII. However, on the controls, most of the FXII was in activated form, whereas on the CBAS and Corline surfaces very little activation occurred.

Kallikrein cascade and cytokines in inflamed joints

Rheumatoid arthritis is a chronic multi-system disease of unknown aetiology. The current hypothesis is that an unknown antigen triggers an autoimmune response in a genetically susceptible individual. The predominant pathological change is that of an inflammatory synovitis, characterised by cellular infiltrates and angiogenesis, with subsequent bone and cartilage destruction. These pathological changes are as a result of the activation of a variety of cells, inflammatory mediators, and effector molecules. The pro-inflammatory kinins and cytokines appear to play a central role in the pathogenesis of rheumatoid arthritis. Sufficient evidence exists that establishes a key role for the kallikrein-kinin cascade in inflamed joints. In addition, there appears to be an inter-relationship between cytokines and kinins in the inflammatory process. Kinins induce the release of cytokines, and cytokines have been shown to augment the effects of kinins. This may lead to an enhancement and perpetuation of the inflammatory process. In this review, we report a first study, correlating markers of disease with the kallikrein-kinin cascade and with cytokines.

Contact activation in shock caused by invasive group A Streptococcus pyogenes

OBJECTIVES

The aim of this study was to characterize abnormalities of coagulation in mice with experimental, invasive group A, streptococcal shock, in an attempt to explain the prolongation of the activated partial thromboplastin time identified in patients with streptococcal toxic shock syndrome.

DESIGN

A longitudinal descriptive animal model study of coagulation times and single coagulation factors in mice infected with Streptococcus pyogenes. This was followed by an experimental study to determine whether streptococci or streptococcal products could activate the human contact system in vitro.

SETTING

University infectious diseases and hemostasis molecular biology laboratories.

SUBJECTS

CD1 outbred mice.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Coagulation times, single factor assays, and bradykinin assays were conducted on murine plasma at different times after streptococcal infection and compared with uninfected mice. In experiments in which streptococcal products were co-incubated with human plasma, we compared coagulation times, single factor assays, and activities against a range of chromogenic substrates with control plasma. In a murine model of streptococcal necrotizing fasciitis, the activated partial thromboplastin times were significantly prolonged in infected mice compared with controls, whereas prothrombin times were normal, suggesting an isolated abnormality of the intrinsic pathway. Bleeding was not seen. Prolongation of activated partial thromboplastin time was associated with reduced factor XII and prekallikrein, whereas levels of factors VIII, IX, XI, and high molecular weight kininogen were elevated. In vitro studies suggested that streptococcal supernatants can activate prekallikrein, in addition to causing plasminogen activation through the action of streptokinase.

CONCLUSIONS

Prolongation of activated partial thromboplastin time in streptococcal toxic shock syndrome is associated with activation of the contact system, possibly contributing to the profound shock associated with streptococcal toxic shock syndrome.

Kallikrein and kallikrein-like proteinases: purification and determination by chromatographic and electrophoretic methods

Kallikreins and kallikrein-like enzymes make up a family of serine proteinases present in tissues and body fluids of mammals and in some snake venoms. This review deals with the procedures of purification, detection and determination of these enzymes by chromatographic and electrophoretic methods. The procedures are reported in tables, described and discussed with the aim of illustrating the state-of-the-art of research in the field.

Partial purification of plasma and tissue kallikreins in psoriatic epidermis

Human psoriatic scale extracts produced kinins from heated plasma (11.3 +/- 5.5 ng kinin/mg protein) and from purified low molecular weight (LMW) bovine kininogen (4.4 +/- 1.7 ng/mg). Sephacryl S-200 gel filtration of the extracts showed three peaks of kininogenase activity with Mr values of 90,000 (K-I), 65,000 (K-II), and 35,000 (K-III). Upon DEAE-Sepharose chromatography of the Sephacryl peaks, K-I activity was found in the nonadsorbed fraction and formed kinins only from heated plasma. Peak K-II activity was resolved into two peaks, K-IIa (in the nonadsorbed fraction), which formed kinins only from heated plasma, and K-IIb (in the adsorbed fraction), which formed kinins from both heated plasma and LMW bovine kininogen. K-III kininogenase activity appeared at the same position as K-IIb and also formed kinins from both substrates. Kininogenases K-I and K-IIa had the same Km value (0.3 mM) with Pro-Phe-Arg-p-nitroanilide(pNA), similar to that found with human plasma kallikrein. The Km value of K-IIb with Val-Leu-Arg-pNA (0.8 mM) was like that found for human salivary kallikrein, whereas K-III had a low affinity for this substrate. Like plasma kallikrein, K-I and K-IIa were inhibited by soybean trypsin inhibitor, but only weakly by aprotinin. In addition the kininogenase activity of both K-I and K-IIa was neutralized by adding antihuman prekallikrein immunoglobulin G (IgG). In contrast, K-IIb and K-III were strongly inhibited by aprotinin but not by soybean trypsin inhibitor, consistent with their being tissue kallikreins. It was confirmed that K-IIb and K-III shares antigenic determinant of urinary kallikrein.

Recent evolutionary divergence of plasma prekallikrein and factor XI

The evolution in mammals of the zymogens of the contact activation system of coagulation (factor XII, prekallikrein and factor XI) has been investigated. The NH2-terminal sequences of human plasma prekallikrein and the heavy and light chains of kallikrein have been determined and compared with those of bovine prekallikrein and of human and bovine factors XII and XI. The human and bovine NH2-terminal sequences of the light chains (catalytic polypeptide) show striking similarities both among themselves and with those of the catalytic polypeptide chains of other coagulation and digestive proteases, indicating a common origin. Comparison of the NH2-terminal sequences of human prekallikrein with those of the bovine prekallikrein and human bovine factors XIa and XIIa indicates a common origin of the heavy chain of kallikrein and factor XIa, different from that of either factor XIIa or other known amino acid sequences. Ancestral sequences for human and bovine prekallikrein and factor XI, deduced by genetic analysis of the minimum number of base changes indicate that the NH2-terminus of prekallikrein and factor XI have evolved at about the same rate. The estimated time for the gene duplication was about 124 million years ago, a value consistent with the age of the mammals.

Action of crotalase, an enzyme with thrombin-like and kallikrein-like specificities, on tripeptide nitroanilide derivatives

Since crotalase has thrombin-like and kallikrein-like functional and structural properties, we compared the actions of crotalase, thrombin and plasma kallikrein on 13 tripeptide nitroanilide substrates. Initial rates of hydrolysis were determined at 27 degrees C, pH 8.3, and used to construct Lineweaver-Burk plots from which Km and Vmax were determined. The ratio of kcat/Km was taken as a measure of enzymatic specificity. Crotalase yielded kcat/Km values for the following nitroanilide substrates in descending order of magnitude: H-D-NLeu-CHA-Arg, H-D-Pro-HHT-Arg, Tos-Gly-Pro-Arg, H-D-PhGly-Phe-Arg, Cbo-Glu(BuO)-Gly-Arg, H-D-But-CHA-Lys, H-D-CHG-But-Arg, H-D-NLeu-HHT-Lys, H-D-HHT-Ala-Arg, Bz-Pro-Phe-Arg, Tos-Gly-Pro-Lys, MeS-Leu-Gly-Arg, MeO-CO-CHG-Gly-Arg. This pattern of specificity correlated only roughly with those of thrombin and kallikrein.