Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.4.21.7 (plasmin)
9,023 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thrombin-activable fibrinolysis inhibitor (TAFI) is a zymogen that inhibits the amplification of plasmin production when converted to its active form (TAFIa). TAFI is structurally very similar to pancreatic procarboxypeptidase B. TAFI also shares high homology in zinc binding and catalytic sites with the second basic carboxypeptidase present in plasma, carboxypeptidase N. We investigated the effects of altering residues involved in substrate specificity to understand how they contribute to the enzymatic differences between TAFI and carboxypeptidase N. We expressed wild type TAFI and binding site mutants in 293 cells. Recombinant proteins were purified and characterized for their activation and enzymatic activity as well as functional activity. Although the thrombin/thrombomodulin complex activated all the mutants, carboxypeptidase B activity of the activated mutants against hippuryl-arginine was reduced. Potato carboxypeptidase inhibitor inhibited the residual activity of the mutants. The functional activity of the mutants in a plasma clot lysis assay correlated with their chromogenic activity. The effect of the mutations on other substrates depended on the particular mutation, with some of the mutants possessing more activity against hippuryl-His-leucine than wild type TAFIa. Thus mutations in residues around the substrate binding site of TAFI resulted in altered C-terminal substrate specificity.
...
PMID:Mutations in the substrate binding site of thrombin-activatable fibrinolysis inhibitor (TAFI) alter its substrate specificity. 1279 75

Neuroleptic malignant syndrome (NMS) is induced by alteration of medication in Parkinson's disease (PD); and blood coagulation disorder is regarded as one of the mechanisms implicated in NMS. We have studied markers of blood coagulation and fibrinolysis in 270 patients with PD and 159 healthy controls matched in age and gender. The average values of prothrombin time (international normalized ratio) and plasma levels of prothrombin fragment(1+2), D-dimer, plasmin-alpha 2 antiplasmin complex, thrombomodulin and E-selectin were higher in patients receiving antiparkinsonian agents as compared to the patients without any medication or healthy controls. The effect of antiparkinsonian drugs was analyzed by dividing the patients into three groups according to the medication: the patients under the combination therapy with levodopa and a dopamine agonist, the patients administered levodopa, and those that received a dopamine agonist. Of the three groups, the patients under the combination therapy had the highest values of these markers, and those treated with only levodopa had the lowest values. PD patients receiving antiparkinsonian drugs are often associated with blood coagulation abnormalities, and plasma hemostatic markers should be routinely assessed in the management of such patients. Further study is needed to determine whether these abnormalities predispose to the development of NMS.
...
PMID:Coagulation-fibrinolysis abnormalities in patients receiving antiparkinsonian agents. 1280 99

Serpins are the predominant protease inhibitors in the higher organisms and are responsible, in humans, for the control of many highly regulated processes including blood coagulation and fibrinolysis. The serpin inhibitory mechanism has recently been revealed by the solution of a crystallographic structure of the final serpin-protease complex. The serpin mechanism, in contrast to the classical lock-and-key mechanism, involves dramatic conformational change in both the inhibitor and the inhibited protein. The final result is a stable covalent complex in which the properties of each component are altered so as to allow clearance from the circulation. Several serpins are involved in hemostasis: antithrombin (AT) inhibits many coagulation proteases, most importantly factor Xa and thrombin; heparin cofactor II (HCII) inhibits thrombin; protein C inhibitor (PCI) inhibits activated protein C and thrombin bound to thrombomodulin; plasminogen activator inhibitor 1 inhibits tissue plasminogen activator; and alpha2-antiplasmin inhibits plasmin. Nearly all of these reactions are accelerated through interactions with glycosaminoglycans (GAGs) such as heparin or heparan sulfate. Recent structures of AT, HCII and PCI have revealed how in each case the serpin mechanism has been fine-tuned by evolution to bring about high levels of regulatory control, and how seemingly disparate mechanisms of GAG binding and activation can share critical elements. By considering the serpins involved in hemostasis together it is possible to develop a deeper understanding of their complex individual roles.
...
PMID:Mechanisms of glycosaminoglycan activation of the serpins in hemostasis. 1287 Dec 89

Plasma levels of soluble fibrin (SF) were measured in 1184 patients with disseminated intravascular coagulation (DIC) according to Japanese Ministry of Health and Welfare (JMHW) criteria. The usefulness of SF for the diagnosis of DIC was compared with other hemostatic molecular markers. Most hemostatic markers were significantly increased in patients with DIC than in those without DIC. Plasma levels of fibrin and fibrinogen degradation products, thrombin-antihtrombin complex, plasmin-plasmin inhibitor complex, D-dimer, thrombomodulin, and SF levels were also significantly higher in those with pre-DIC than in those without DIC. In classification of overt DIC by International Society of Thrombosis and Haemostasis (ISTH) criteria, most hemostatic markers were significantly increased in patients with overt DIC than in those without overt DIC. Plasma levels of SF 'in patients with DIC were significantly higher than those in patients with pre-DIC, which were significantly higher than in those without DIC. Plasma levels of SF were also significantly higher in patients with overt DIC than in those with non-overt DIC. The correlation between plasma SF levels and DIC score according to JMHW criteria or ISTH criteria was good. Receiver operating characteristic analysis shows that SF was the best marker for the diagnosis of DIC or overt DIC. These findings suggest that plasma SF might be useful marker for the diagnosis of DIC or overt DIC.
...
PMID:Increased soluble fibrin in plasma of patients with disseminated intravascular coagulation. 1450 12

The latent plasma carboxypeptidase thrombin-activable fibrinolysis inhibitor (TAFI) is activated by thrombin/thrombomodulin on the endothelial cell surface, and functions in dampening fibrinolysis. In this study, we examined the effect of activated TAFI (TAFIa) in modulating the proinflammatory functions of bradykinin, complement C5a, and thrombin-cleaved osteopontin. Hydrolysis of bradykinin and C5a and thrombin-cleaved osteopontin peptides by TAFIa was as efficient as that of plasmin-cleaved fibrin peptides, indicating that these are also good substrates for TAFIa. Plasma carboxypeptidase N, generally regarded as the physiological regulator of kinins, was much less efficient than TAFIa. TAFIa abrogated C5a-induced neutrophil activation in vitro. Jurkat cell adhesion to osteopontin was markedly enhanced by thrombin cleavage of osteopontin. This was abolished by TAFIa treatment due to the removal of the C-terminal Arg168 by TAFIa from the exposed SVVYGLR alpha 4 beta 1 integrin-binding site in thrombin-cleaved osteopontin. Thus, thrombin cleavage of osteopontin followed by TAFIa treatment may sequentially up- and down-modulate the pro-inflammatory properties of osteopontin. An engineered anticoagulant thrombin, E229K, was able to activate endogenous plasma TAFI in mice, and E229K thrombin infusion effectively blocked bradykinin-induced hypotension in wild-type, but not in TAFI-deficient, mice in vivo. Our data suggest that TAFIa may have a broad anti-inflammatory role, and its function is not restricted to fibrinolysis.
...
PMID:Thrombin activatable fibrinolysis inhibitor, a potential regulator of vascular inflammation. 1452 95

Kidney transplant recipients are not only prone to dyslipidemia but also have a high risk of cardiovascular death. Impairment of the fibrinolytic system is thought to be one factor playing a role in development of thrombotic complications. Thrombin-activatable fibrinolysis inhibitor (TAFI) is a glycoprotein, linking coagulation and fibrinolysis. The purpose of this study was to assess TAFI concentrations and activities in renal transplant recipients stratified based upon serum cholesterol values above 220 mg/dL or below 200 mg/dL. The groups did not differ regarding age, creatinine clearance, BMI, time after transplantation, albumin, fibrinogen, thrombomodulin, or PAP. Additionally, we evaluated thrombin activity (thrombin-antithrombin complex TAT, prothrombin fragments 1 + 2); TAFI activator; thrombomodulin (TM), catalyzer of TAFI activation; and the degree of plasmin generation (plasmin-antiplasmin complex PAP) using commercially available kits. In patients with hyperlipidemia significantly higher TAFI concentrations and activities may contribute to prolonged ECLT and lowered fibrinolytic activity index (FAI). Increased levels of F1 + 2 and TAT were observed in hypercholesterolemic patients, indicating enhanced thrombin generation. Elevated TAFI concentration, and activities and enhanced thrombin generation observed in hypercholesterolemic kidney transplant recipients may contribute to hypofibrinolysis and progression of atherosclerosis in this group of patients.
...
PMID:Thrombin-activatable fibrinolysis inhibitor in kidney transplant recipient with dyslipidemia. 1452 94

Thrombin activatable fibrinolysis inhibitor (TAFI) is a carboxypeptidase B-like proenzyme, which is synthesized in the liver and circulates in the blood at a concentration of about 275 nmol/l. Once activated, by thrombin or plasmin, TAFI down regulates fibrinolysis, slowing clot lysis by cleaving the C-terminal lysine and arginine residues from partially degraded fibrin. Thrombomodulin enhances thrombin activation of TAFI by more than 1000-fold, suggesting that the thrombin-thrombomodulin complex is the physiological activator of TAFI. Activated protein C can up-regulate fibrinolysis by limiting the activation of TAFI via the attenuation of thrombin production. While impairment of fibrinolysis may predispose to thrombosis, excessive fibrinolysis may result in a bleeding tendency. In acquired coagulopathies, TAFI antigen levels are reduced in patients with disseminated intravascular coagulation. In focusing on women with major post-partum haemorrhage requiring blood transfusion, a significant reduction in TAFI levels is observed. The precise degree of TAFI activation is currently being characterized using new and more specific assays. The resulting data may provide insight into therapeutic options to treat post-partum haemorrhage, which is associated with significant morbidity.
...
PMID:Characterization of thrombin activatable fibrinolysis inhibitor in normal and acquired haemostatic dysfunction. 1456 41

Patients with end-stage renal disease dialyzed due to diabetic nephropathy are at higher risk of death due to cardiovascular complications than dialyzed non-diabetic patients. Disturbances in hemostasis may play a role in the vascular complications of diabetes mellitus. It has been postulated that TAFI-Thrombin Activatable Fibrinolysis Inhibitor, newly described glycoprotein, couples two opposite systems: coagulation and fibrinolysis. The aim of the work was to study TAFI concentration in hemodialyzed and peritoneally dialyzed diabetic and non-diabetic patients. We assessed: TAFI concentration, markers of ongoing coagulation: thrombin-antithrombin complexes, prothrombin fragments 1 + 2 (markers of TAFI activation), a marker of ongoing fibrinolysis: plasmin-antiplasmin complexes, a marker of TAFI cataliser to TAFIa-thrombomodulin using commercially available kits. All four groups studied did not differ in regard to fibrinogen, thrombomodulin, plasmin-antiplasmin complexes, and TAFI concentration. Both groups of dialyzed diabetic patients have higher concentration of markers of ongoing coagulation when compared to dialyzed non-diabetic patients. Hypercoagulable state observed in dialyzed diabetic patients may contribute to the higher cardiovascular mortality in these population.
...
PMID:[Thrombin activatable fibrinolysis o inhibitor-TAFI- in dialyzed patients with diabetic nephropathy]. 1468 22

Cyclosporine (CyA) has been implicated to increase cardiovascular morbidity and mortality after renal transplantation. Impairment of the fibrinolytic system is one factor involved in the development of thrombotic complications. The aim of this study was to compare hematological and hemostatic parameters among patients on CyA, azathioprine, and prednisone (n = 31) versus CyA and steroids (n = 14). Using commercially available kits we evaluated thrombin activity as thrombin-antithrombin complexes (TAT), prothrombin fragments (1 + 2), thrombin activatable fibrinolysis inhibitor-(TAFI), TAFI activator, thrombomodulin (TM)-a marker for endothelial cell injury,-plasmin generation (plasmin-antiplasmin complex PAP), a glycoprotein linking coagulation and fibrinolysis. We observed that patients not treated with azathioprine displayed longer prothrombin times and activated partial thromboplastin times; higher fibrinogen, platelet counts and fibrinolytic activity index (FAI); shorter euglobulin clot lysis time; as well as lower thrombin generation markers namely, prothrombin fragments 1 + 2 and thrombin-antithrombin complexes. Although patients in the non-AZA group tended to have been engrafted for a longer time (P =.086), the groups did not differ with regard to age, BMI, erythrocyte count, hematocrit, leukocyte count, creatinine clearance, alanine and asparagine aminotransferase activities mean arterial blood pressure, fibrinogen, TAFI, thrombomodulin, or plasmin-antiplasmin complexes. These findings suggest that kidney transplant recipients on triple therapy are at greater risk of cardiovascular disease than those without azathioprine treatment, despite the lower fibrinolytic activity.
...
PMID:Some aspects of hemostasis in kidney transplant recipients maintained on cyclosporine, azathioprine, and prednisone in comparison to patients treated with cyclosporine and prednisone. 1469 44

In an in vitro clot lysis model in human plasma, carboxypeptidase U (CPU) is generated by thrombin following the coagulation and by plasmin at the later stage of clot lysis. CPU is able to slow down clot lysis by suppressing the cofactor activity of partially degraded fibrin in the plasminogen activation by tissue-type plasminogen activator (t-PA). Making use of thrombomodulin and a thrombin inhibitor, the generation of CPU during the in vitro clot lysis can be manipulated both in terms of magnitude and time course. The data obtained demonstrate that CPU affects the clot dissolution through a threshold-dependent mechanism: as long as the CPU activity remains above the threshold value, lysis is prevented from proceeding into the propagation phase. From the moment the CPU activity drops below this threshold value, the rate of lysis accelerates. This threshold value for CPU activity is dictated by the t-PA concentration: increasing the t-PA concentration increases the CPU threshold and vice versa. This implies that the effect of the CPU pathway will become more apparent at a lower fibrinolytic capacity. Our threshold-based hypothesis indicates that the time course of proCPU activation, the stability of CPU and the t-PA concentration all play a crucial role in determining the result of the in vitro clot lysis experiment. Furthermore, this hypothesis provides us with new insights into previously published data on the effects of CPU on in vitro clot lysis by high and low t-PA concentrations.
...
PMID:Carboxypeptidase U (TAFIa) prevents lysis from proceeding into the propagation phase through a threshold-dependent mechanism. 1740 10


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---