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Journal of Applied Physiology:... May 1980We measured products of thrombin and plasmin action and of the platelet release reaction during exercise to determine if the well-known effect of exercise on in vitro... (Comparative Study)
Comparative Study
We measured products of thrombin and plasmin action and of the platelet release reaction during exercise to determine if the well-known effect of exercise on in vitro coagulation and fibrinolytic tests reflects activity of these systems in vivo. Plasma fibrinopeptide A, produced by thrombin-mediated proteolysis of fibrinogen, increased with graded treadmill and cycle exercise to postexercise levels of 20--30 times resting values. Fibrin/fibrinogen-related D antigen increased in a similar fashion with peak levels at maximal O2 uptake. Plasma-activated partial thromboplastin times fell as fibrinopeptide A levels increased. Unheated fibrin plate lysis areas increased as D antigen concentrations rose, indicating increased release of plasminogen activator. In contrast to activation of the soluble coagulation and fibrinolytic systems, platelet counts and plasma levels of beta-thromboglobulin, a platelet release protein, did not change significantly with exercise. The effect of exercise on thrombin and plasmin was not influenced by prior physical training, but appeared to be less with cycle exercise than with treadmill exercise.
Topics: Blood Coagulation; Blood Platelets; Fibrinolysin; Humans; Male; Physical Exertion; Thrombin
PubMed: 6450195
DOI: 10.1152/jappl.1980.48.5.821 -
Redox Report : Communications in Free... 2002It is thought that disulfide bonds in secreted proteins are inert because of the oxidizing nature of the extracellular milieu. We have suggested that this is not... (Review)
Review
It is thought that disulfide bonds in secreted proteins are inert because of the oxidizing nature of the extracellular milieu. We have suggested that this is not necessarily the case and that certain secreted proteins contain one or more disulfide bonds that can be cleaved and that this cleavage is central to the protein's function. This review discusses disulfide bond cleavage in the secreted soluble protein, plasmin. Cleavage of plasmin disulfide bond(s) triggers peptide bond cleavage and formation of the tumour angiogenesis inhibitor, angiostatin. Tumour cells secrete phosphoglycerate kinase which facilitates cleavage of the plasmin disulfide bond(s). Phosphoglycerate kinase is not a conventional disulfide bond reductase. We propose that phosphoglycerate kinase facilitates cleavage of a particular plasmin disulfide bond by hydroxide ion, which results in formation of a sulfenic acid and a free thiol. The free thiol is then available to exchange with another nearby disulfide bond resulting in formation of a new disulfide and a new free thiol. The reduced plasmin is then susceptible to discreet proteolysis which results in release of angiostatin.
Topics: Amino Acid Sequence; Animals; Disulfides; Fibrinolysin; Humans; Hydrolysis; Molecular Sequence Data; Neovascularization, Pathologic; Neovascularization, Physiologic; Plasminogen; Proteins
PubMed: 12189052
DOI: 10.1179/135100002125000299 -
Journal of Clinical Pathology May 1969
Topics: Fibrinogen; Fibrinolysin; Humans; Immunoassay; Macroglobulins; Streptokinase; Trypsin Inhibitors
PubMed: 4239466
DOI: 10.1136/jcp.22.3.371-b -
Blood Coagulation & Fibrinolysis : An... Jun 2007
Topics: Fibrinolysin; Humans; Male; Semen; Thrombin
PubMed: 17473585
DOI: 10.1097/MBC.0b013e3280d21ad9 -
Thrombosis Research Aug 1988Denaturation of human plasmin in solutions of various pH levels was studied. The denaturation and loss of catalytic activity of plasmin in solutions of between pH 3.5...
Denaturation of human plasmin in solutions of various pH levels was studied. The denaturation and loss of catalytic activity of plasmin in solutions of between pH 3.5 and 10.5 is a second-order kinetics. In alkaline solutions of pH levels greater than 11.5, plasmin undergoes a first-order denaturation. The second-order denaturation of plasmin is mainly due to the autolytic reactions between plasmin molecules. Two autolytic processes of human plasmin in aqueous solution were observed. In a slightly acidic solution (pH 6.5) the light (B) chain was found to be cleaved faster than the heavy (A) chain of plasmin. On the other hand, the heavy (A) chain was cleaved in an alkaline solution of pH near 11.0. A cleaved heavy (A) chain of molecular weight 58,000 was observed. Both the heavy (A) chain and the light (B) chain were found to be cleaved at pH levels between 6.5 and 11.0. The loss of the esterase activity of plasmin samples in the autolytic process is in parallel with the decline of intact light (B) chain. The autolytic cleavage of the heavy (A) chain led to the formation of a new type of catalytically active plasmin.
Topics: Autolysis; Fibrinolysin; Humans; Hydrogen-Ion Concentration; In Vitro Techniques; Kinetics; Molecular Weight; Protein Conformation; Protein Denaturation
PubMed: 2973156
DOI: 10.1016/0049-3848(88)90371-4 -
Archivos de La Sociedad Espanola de... Jun 2015To determine whether intravitreal injection of autologous plasmin enzyme (APE) is effective in vitreomacular traction syndrome (VMTS) by improving visual acuity and... (Clinical Trial)
Clinical Trial
PURPOSE
To determine whether intravitreal injection of autologous plasmin enzyme (APE) is effective in vitreomacular traction syndrome (VMTS) by improving visual acuity and restoring macular morphology.
METHODS
A prospective study of 11 consecutive patients diagnosed with VMTS in the Ophthalmology Department from January to May, 2011.
INCLUSION CRITERIA
best corrected visual acuity (BCVA) less than 0.5, and vitreomacular attachment in foveal area resulting in macular thickness>250 microns diagnosed by optical coherence tomography (Cirrus OCT, Carl Zeiss Meditec, Inc, Oberkochen, Germany).
EXCLUSION CRITERIA
active proliferative diabetic retinopathy, axial myopia>26mm, vitrectomy, glaucoma, previous intravitreal injections and previous rhegmatogenous detachment. One to 3 monthly intravitreal injections of 0.2ml of APE were applied, interrupting if posterior vitreous detachment was attained. Wilcoxon's test was used for statistical analysis.
RESULTS
A total of 12 eyes of 11 patients were treated. A complete posterior vitreous detachment was achieved in 4 (33%) eyes at the end of the study, 2 of them with one injection, and 2 with 3 monthly injections. Improvement of BCVA was statistically significant (P=.017) and the decrease in central macular thickness also was statistically significant (P=.016). There was only one complication: intraocular hypertension after injection that subsided with a new paracentesis.
CONCLUSIONS
Intravitreal APE injections avoided vitrectomy in VMTS in one in every 3 patients.
Topics: Aged; Aged, 80 and over; Female; Fibrinolysin; Humans; Intravitreal Injections; Macula Lutea; Male; Ocular Hypotension; Prospective Studies; Stress, Mechanical; Syndrome; Treatment Outcome; Vitreous Detachment
PubMed: 25843697
DOI: 10.1016/j.oftal.2014.04.016 -
Applied Microbiology and Biotechnology Sep 1997Heterologous production of bovine plasmin was studied in the industrially relevant bacterium Lactococcus lactis. Two sets of lactococcal gene expression signals were...
Heterologous production of bovine plasmin was studied in the industrially relevant bacterium Lactococcus lactis. Two sets of lactococcal gene expression signals were coupled to the region of the plasmin gene coding for the serine protease domain. When the promoter region of the prtP gene was used, plasmin was detected mainly intracellularly in strain BPL25 by Western blot hybridization. The intracellular presence of plasmin led to physiological stress. Expression of the plasmin gene driven by the promoter and complete signal sequence of the lactococcal usp45 gene resulted in efficient plasmin secretion in strain BPL420. Cell lysis was observed in strains producing plasmin fragments including the catalytic domain, but not in control strains, which only produced a non-catalytic region of plasmin. The plasmin produced was shown to be biologically active.
Topics: Animals; Base Sequence; Cattle; Fibrinolysin; L-Lactate Dehydrogenase; Lactococcus lactis; Molecular Sequence Data; Recombinant Proteins
PubMed: 9352676
DOI: 10.1007/s002530051058 -
Journal of Biochemistry Jul 1980Fluorogenic peptides, peptidyl-4-methylcoumaryl-7-amides (MCA), containing COOH-terminal lysine residues, were newly synthesized and tested as substrates for plasmin....
Fluorogenic peptides, peptidyl-4-methylcoumaryl-7-amides (MCA), containing COOH-terminal lysine residues, were newly synthesized and tested as substrates for plasmin. Among six peptidyl-MCA's, Boc-Val-Leu-Lys-MCA and Boc-Glu-Lys-Lys-MCA were found to be useful for the specific and sensitive assay of plasmin. The Km values estimated from Line-weaver-Burk plots for these substrates using human and bovine plasmins were in the region of 10(-4) M. Boc-Glu-Lys-Lys-MCA was slightly hydrolyzed by bovine plasma kallikrein, and Boc-Val-Leu-Lys-MCA was slightly hydrolyzed by human and hog urinary kallikreins and hog pancreatic kallikrein. However, both of the fluorogenic peptides were essentially unaffected by urokinase, alpha-thrombin, Factor Xa, Factor IXa, Factor XIa, and Factor XIIa. It was confirmed that plasmin hydrolyzed Boc-Glu-Lys-Lys-MCA, cleaving the lysyl-MCA bond, but not the lysyl-lysyl bond. These fluorogenic peptides were resistant to human plasmin activated by streptokinase. Boc-Glu-Lys-Lys-MCA was not hydrolyzed by human plasmin or plasminogen in the presence of more than a 5-fold molar excess of streptokinase. The sensitivity of Boc-Val-Leu-Lys- of more than a 5-fold molar excess of streptokinase. The sensitivity of Boc-Val-Leu-Lys-MCA to human plasmin was also reduced, but plasmin retained 35% of the maximum activity even in the presence of a 20-fold molar excess of streptokinase. These results suggest that streptokinase-plasmin complex has essentially no activity towards Boc-Glu-Lys-Lys-MCA.
Topics: Animals; Cattle; Coumarins; Enzyme Activation; Fibrinolysin; Humans; Kinetics; Peptides; Plasminogen; Streptokinase; Substrate Specificity; Urokinase-Type Plasminogen Activator
PubMed: 6447693
DOI: No ID Found -
Growth Hormone & IGF Research :... Aug 2008To determine if plasmin differentially augments platelet aggregation through variable efficiencies of IGF-IGFBP complex cleavage.
OBJECTIVES
To determine if plasmin differentially augments platelet aggregation through variable efficiencies of IGF-IGFBP complex cleavage.
METHODS
We utilized ADP-triggered platelet aggregation assays to test the effects of IGF-I versus IGF-II in complex with IGFBP-2 or IGFBP-3 upon the efficiency of plasmin (a known IGFBP protease) as a pro-aggregatory stimulus. In vitro proteolysis assays were performed as controls.
RESULTS
We found that IGF-I complexes augmented platelet-mediated aggregation whereas IGF-II either had no effect (IGFBP-2) or inhibited platelet-mediated aggregation (IGFBP-3). In vitro proteolysis assays of IGFBP-2 and IGFBP-3 using plasmin revealed that three of the four aggregation findings were explained by the disparate efficiencies of IGFBP proteolysis associated with each IGF. Only IGF-II-IGFBP-2 complex resulted in a finding that could not be explained by the concept of differential regulation of plasmin's proteolysis efficiency by the two IGF ligands.
CONCLUSIONS
Our findings demonstrate that the plasmin can differentially modulate platelet aggregation in response to intrinsic heterogeneities within the IGF axis.
Topics: Blood Platelets; Fibrinolysin; Humans; Indomethacin; Insulin-Like Growth Factor Binding Proteins; Models, Biological; Multiprotein Complexes; Platelet Aggregation; Protein Binding; Protein Processing, Post-Translational; Somatomedins
PubMed: 18328759
DOI: 10.1016/j.ghir.2008.01.004 -
Research Communications in Molecular... Jun 1997This study was undertaken to determine if reocclusion after treatment of myocardial infarction with a tissue-plasminogen activator (t-PA) may be due to plasmin-induced...
This study was undertaken to determine if reocclusion after treatment of myocardial infarction with a tissue-plasminogen activator (t-PA) may be due to plasmin-induced platelet aggregation. t-PA caused platelet aggregation by conversion of plasminogen to plasmin under certain conditions. Plasmin-induced platelet aggregation was inhibited by serine protease inhibitors, aprotinin and bdellin, and a lysine binding site inhibitor, epsilon-aminocaproic acid (EACA). Extracellular [Ca2+], and RGDS sequence-dependent steps were involved in the aggregation process. The action of plasmin was inhibited by large thrombin antagonistic molecules such as argatroban-inactivated thrombin or anti-thrombin receptor peptide antibodies but not by small molecules like thrombin receptor antagonist peptides. This suggests that target molecules of plasmin on the surface of platelets may not be thrombin receptors but may exist very close to thrombin receptors. Binding experiments using FITC-labeled plasmin showed that plasmin has its binding sites on platelets. Flow cytometric analyses with four types of anti-plasmin(ogen) monoclonal antibodies suggested that plasmin might bind to platelets through the N-terminal region. The binding of plasmin to platelets was suppressed by aprotinin and EACA, furthermore indicating that protease catalytic sites and lysine binding regions are involved in interaction of plasmin to platelet.
Topics: Aminocaproic Acid; Aprotinin; Blood Platelets; Cell Membrane; Fibrinolysin; Hirudins; Humans; In Vitro Techniques; Organic Chemicals; Platelet Aggregation; Platelet Aggregation Inhibitors; Protease Inhibitors; Serine Proteinase Inhibitors; Tissue Plasminogen Activator
PubMed: 9261893
DOI: No ID Found