Search results for "High-molecular-weight kininogen"
showing 7 items of 7 documents
Analysis of cold activation of the contact system in hereditary angioedema with normal C1 inhibitor.
2021
Hereditary angioedema (HAE) attacks are caused by excessive activation of the contact system. Understanding how the contact system is activated in HAE, especially in patients with normal C1 inhibitor (HAEnCI), is essential to effectively treat this disease. Contact system activation involves the cleavage of several proteins including Factor XII (FXII), high molecular weight kininogen (HK), prekallikrein, sgp120 (ITIH4) and C1 inhibitor (C1-INH) before the subsequent generation of bradykinin that mediates HAE. In this study, we evaluated the fragmentation and enzymatic activity of contact system proteins in HAEnCI plasma samples before and after contact system activation induced by incubatio…
Parallel reduction of plasma levels of high and low molecular weight kininogen in patients with cirrhosis
1999
SummaryLittle is known about the regulation of high-molecular-weight-kininogen (HK) and low-molecular-weight-kininogen (LK) or the relationship of each to the degree of liver function impairment in patients with cirrhosis. In this study, we evaluated HK and LK quantitatively by a recently described particle concentration fluorescence immunoassay (PCFIA) and qualitatively by SDS PAGE and immunoblotting analyses in plasma from 33 patients with cirrhosis presenting various degrees of impairment of liver function. Thirty-three healthy subjects served as normal controls. Patients with cirrhosis had significantly lower plasma levels of HK (median 49 μg/ml [range 22-99 μg/ml]) and LK (58 μg/ml [15…
Mapping the cell binding site on high molecular weight kininogen domain 5.
1995
Investigations mapped the region(s) on the light chain of high molecular weight kininogen (HK) that participates in cell binding. Sequential and overlapping peptides of domain 5 (D5H) were synthesized to determine its cell binding site(s). Three peptides from non-overlapping regions on D5H were found to inhibit biotin-HK binding to endothelial cells. Peptides GKE19 and HNL 21 weakly inhibited biotin-HK binding with IC50 of 792 and 215 microM, respectively. Peptide HKH20 inhibited biotin-HK binding with an IC50 of 0.2 microM. Two peptides, GGH18 and HVL24, which overlapped HKH20, also inhibited biotin-HK binding to endothelial cells with IC50 values of 108 and 0.8 microM, respectively. Bioti…
Mapping of the high molecular weight kininogen binding site of prekallikrein. Evidence for a discontinuous epitope formed by distinct segments of the…
1993
Prekallikrein, a glycoprotein involved in contact phase activation, circulates in plasma in the form of a binary complex with high molecular weight kininogen (H-kininogen). The binding to H-kininogen is mediated by the prekallikrein heavy chain consisting of four repetitive domains, A1-A4. To define more precisely the region(s) involved in kininogen binding, we have employed an affinity cross-linking strategy with a synthetic peptide of 31 residues which mimics the prekallikrein binding site of H-kininogen. Cross-linking of the radiolabeled peptide to (pre)kallikrein revealed a binding segment in the NH2-terminal portion of the prekallikrein heavy chain; another binding segment was located …
Mapping of the Discontinuous H-kininogen Binding Site of Plasma Prekallikrein
1999
Plasma prekallikrein, a zymogen of the contact phase system, circulates in plasma as heterodimeric complex with H-kininogen. The binding is mediated by the prekallikrein heavy chain consisting of four apple domains, A1 to A4, to which H-kininogen binds with high specificity and affinity (K(D) = 1.2 x 10(-8) M). Previous work had demonstrated that a discontinuous kininogen-binding site is formed by a proximal part located in A1, a distal part exposed by A4, and other yet unidentified portion(s) of the kallikrein heavy chain. To detect relevant binding segment(s) we recombinantly expressed single apple domains and found a rank order of binding affinity for kininogen of A2 > A4 approximately A…
Severe High Molecular Weight Kininogen (HK) Deficiency: Clinical Characteristics, Deficiency-Causing KNG1 Variants in Reported and New Cases, and Est…
2021
Abstract Background: Severe high molecular weight kininogen (HK) deficiency is an autosomal recessive defect of the contact system caused by mutations in KNG1. Limited scientific interest in HK deficiency due to the rarity of the seemingly asymptomatic condition may increase, as HK, the precursor of bradykinin, is now discussed as a therapeutic target e.g. in hereditary angioedema. Aims: We provide a comprehensive analysis of the diagnostic, clinical, and genetic features of HK deficiency and estimate its frequency. Methods: We identified a new case of HK deficiency, systematically review the literature, conduct new genetic studies of reported cases, and comprehensively analyze the clinical…
Hereditary angioneurotic oedema and blood-coagulation: interaction between C1-esterase-inhibitor and the activation factors of the proteolytic enzyme…
1983
C-1-inactivator (C-1-INA) does not only exert its important inhibitory functions in the complement system but also in the first step in the activation of the coagulation, fibrinolytic and kallikrein system. We therefore determined in nine patients with hereditary angioneurotic oedema (HANE) with obvious quantitative or functional defects of C-1-INA, and one further patient with Quincke-type oedema of different origin, the coagulation factors of the initial phase such as Hageman factor, plasma thromboplastin antecedent (PTA) and high molecular weight kininogen (HMWK). These factors were further correlated with the concentration as well as functional activity of C-1-INA. Nine of ten patients …