Lagopsis supina extract and its fractions exert prophylactic effects against blood stasis in rats via anti-coagulation, anti-platelet activation and anti-fibrinolysis and chemical characterization by UHPLC-qTOF-MS/MS.

Lagopsis supina (Steph.) IK. -Gal. ex Knorr. has been used for centuries as an empiric treatment for blood stasis syndrome in China without scientific validation. The aim of this study was to evaluate for the first time the chemical profiling, efficacy and mechanism of L. supina ethanol extract (LS) and its four fractions (LSA∼D) in Dextran 500-induced acute blood stasis model rats. Oral administration of LS (229.0∼916.0 mg/kg) and LSC (17.6∼70.4 mg/kg) once daily for seven consecutive days significantly improved microcirculation hemodynamics function (blood flow, blood concentration and blood flow velocity), hemorheological parameters (whole blood viscosity, whole blood reduced viscosity, plasma viscosity, platelet aggregation rate, hematokrit, erythrocyte assembling index and erythrocyte deformation index), and coagulation parameters (thrombin time, prothrombin time, activated partial thromboplastin time, fibrinogen and antithrombin III). Furthermore, their markedly down-regulated thromboxane B2 and 6-keto-prostaglandin F1α levels. In addition, it significantly decreased tissue-type plasminogen activator (t-PA), urokinasetype plasminogen activator (u-PA) and plasminogen activator inhibitor-1 (PAI-1) levels, as well as PAI-1/t-PA and PAI-1/u-PA rations. In parallel, 51 chemical constituents were identified from LS based on ultra-high-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UHPLC-qTOF-MS/MS), and quantitative analysis showed that the two major constituents of stachysoside A and acteoside were present in 0.90 ± 0.01 and 1.36 ± 0.01 mg/g of the L. supina whole plant, respectively. These findings suggest that LS and LSC possess prominent anti-blood stasis effect on rats by modulating the anti-coagulation, anti-platelet activation and anti-fibrinolysis, and supports the traditional folk use of this plant.

Dehydrodieugenol B and hexane extract from Endlicheria paniculata regulate inflammation, angiogenesis, and collagen deposition induced by a murine sponge model.

The present study reports the evaluation of hexane extract from Endlicheria paniculata and its main metabolite dehydrodieugenol B in the inflammatory response induced by a murine implant sponge model. As a result, a reduction in the inflammatory markers (myeloperoxidase and N-acetyl-ß-D-glucosaminidase) and number of mast cells were observed in comparison to the control group. All doses were also able to reduce angiogenic parameters evaluated in fibrovascular tissue. In implants treated with dehydrodieugenol B a reduction in total collagen deposition and types I and III collagen fibers were observed, while an increased in total collagen deposition and types I and III collagen fibers were observed in the treatment with hexane extract. Docking studies into cyclooxygenase-2 active site revealed that the dehydrodieugenol B had binding modes and energies comparable with celecoxib, diclofenac and ibuprofen. Therefore, dehydrodieugenol B was able to alter key components of chronic inflammation, resulting in a reduced inflammatory response and also presenting antifibrogenic and antiangiogenic effects. However, treatment with hexane extract resulted in a reduced inflammatory response with antiangiogenic effects, but caused fibrogenic effects.

In vitro screening for compounds from Hypericum longistylum with anti-pulmonary fibrosis activity.

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with a poor prognosis and limited therapies, and transforming growth factor-ß1 (TGF-ß1) plays a central role in the pathogenesis of IPF. Here, we aimed to investigate the chemical constituents and biological activities of Hypericum longistylum and detect whether the isolated compounds inhibit the TGF-ß1/Smad3 signaling pathway to identify candidate compounds for the treatment of pulmonary fibrosis. Fifteen compounds (1-15) were isolated from H. longistylum and their structures were elucidated on the basis of spectroscopic analyses. An in vitro MTT assay was used to test the effect of these fifteen compounds on fibroblast cytotoxicity and vitality. Furthermore, their bioactivities were screened using a TGF-ß1/Smad3 pathway luciferase reporter in vitro. MTT screening found that compounds 1-15 had no deleterious effects on normal mouse lung fibroblasts and no significant inhibition of vitality. Luciferase assay showed that compounds 14 and 15 could significantly inhibit the TGF-ß1/Smad3 pathway with the inhibition rates of 67.92% and 93.10%, respectively. Both compounds can be used as lead compounds for structural modification and optimization to obtain more drug candidates for the treatment of pulmonary fibrosis.

Bioactivity Profiling of Small-Volume Samples by Nano Liquid Chromatography Coupled to Microarray Bioassaying Using High-Resolution Fractionation.

High-throughput screening platforms for the identification of bioactive compounds in mixtures have become important tools in the drug discovery process. Miniaturization of such screening systems may overcome problems associated with small sample volumes and enhance throughput and sensitivity. Here we present a new screening platform, coined picofractionation analytics, which encompasses microarray bioassays and mass spectrometry (MS) of components from minute amounts of samples after their nano liquid chromatographic (nanoLC) separation. Herein, nanoLC was coupled to a low-volume liquid dispenser equipped with pressure-fed solenoid valves, enabling 50-nL volumes of column effluent (300 nL/min) to be discretely deposited on a glass slide. The resulting fractions were dried and subsequently bioassayed by sequential printing of nL-volumes of reagents on top of the spots. Unwanted evaporation of bioassay liquids was circumvented by employing mineral oil droplets. A fluorescence microscope was used for assay readout in kinetic mode. Bioassay data were correlated to MS data obtained using the same nanoLC conditions in order to assign bioactives. The platform provides the possibility of freely choosing a wide diversity of bioassay formats, including those requiring long incubation times. The new method was compared to a standard bioassay approach, and its applicability was demonstrated by screening plasmin inhibitors and fibrinolytic bioactives from mixtures of standards and snake venoms, revealing active peptides and coagulopathic proteases.

Browplasminin, a condensed tannin with anti-plasmin activity isolated from an aqueous extract of Brownea grandiceps Jacq. flowers.

ETHNOPHARMACOLOGICAL RELEVANCE: Following Venezuelan traditional medicine, females with heavy menstrual blood loss (menorrhagia) drink Brownea grandiceps Jacq. flowers (BG) decoctions to reduce the bleeding. In a previous study, we demonstrated that BG aqueous extract (E) possesses a potent anti-fibrinolytic activity capable of inhibiting plasmin, the main serine-protease that degrades fibrin. It is widely known that plasmin inhibitors are often used as anti-fibrinolytics to reduce bleeding during surgeries with high risk of blood loss such as cardiac, liver, vascular, tooth extraction and large orthopedic procedures, as well as for menorrhagia treatments. The aim of this work was to isolate and characterize from BGE the compound responsible for the reported anti-fibrinolytic activity. MATERIALS AND METHODS: A decoction of BG was prepared; then it was homogenized, centrifuged and lyophilized to obtain BGE. Subsequently the extract was fractionated by gel filtration and reverse phase using HPLC and the active compound was characterized by MALDI-ToF MS. The kinetic parameters of anti-plasmin activity were evaluated by an amidolytic assay using a chromogenic substrate; also the anti-plasmin activity was estimated by fibrin plate method. Data were analyzed by nonparametric statistics. RESULTS: The active compound was a condensed tannin denominated Browplasminin, which is capable of inhibiting the plasmin activity in a dose-dependent manner when measured in fibrin plates or by the amidolytic activity method; it also has a minor effect on the FXa activity. However, it does not affect the activity of other serine-proteases such as trypsin, t-PA or u-PA. Browplasminin consists predominately of heteroflavan-3-ols of catechin with B-type linkages, and extents up to heptadecamers (~ 5000Da), with hexose residues attached to the polymer that presents a high degree of galloylation. Its IC50 for plasmin was 47.80µg/mL and for FXa was 237.08µg/mL, while the Ki were 0.76 and 61.61µg/mL for plasmin and FXa, respectively. CONCLUSIONS: The overall outcome of this study suggests that Browplasminin could be responsible for reducing heavy menstrual bleeding in women because its kinetic parameters showed that is a good plasmin inhibitor.

Purification and characterization of tenerplasminin-1, a serine peptidase inhibitor with antiplasmin activity from the coral snake (Micrurus tener tener) venom.

A plasmin inhibitor, named tenerplasminin-1 (TP1), was isolated from Micrurus tener tener (Mtt) venom. It showed a molecular mass of 6542Da, similarly to Kunitz-type serine peptidase inhibitors. The amidolytic activity of plasmin (0.5nM) on synthetic substrate S-2251 was inhibited by 91% following the incubation with TP1 (1nM). Aprotinin (2nM) used as the positive control of inhibition, reduced the plasmin amidolytic activity by 71%. Plasmin fibrinolytic activity (0.05nM) was inhibited by 67% following incubation with TP1 (0.1nM). The degradation of fibrinogen chains induced by plasmin, trypsin or elastase was inhibited by TP1 at a 1:2, 1:4 and 1:20 enzyme:inhibitor ratio, respectively. On the other hand, the proteolytic activity of crude Mtt venom on fibrinogen chains, previously attributed to metallopeptidases, was not abolished by TP1. The tPA-clot lysis assay showed that TP1 (0.2nM) acts like aprotinin (0.4nM) inducing a delay in lysis time and lysis rate which may be associated with the inhibition of plasmin generated from the endogenous plasminogen activation. TP1 is the first serine protease plasmin-like inhibitor isolated from Mtt snake venom which has been characterized in relation to its mechanism of action, formation of a plasmin:TP1 complex and therapeutic potential as anti-fibrinolytic agent, a biological characteristic of great interest in the field of biomedical research. They could be used to regulate the fibrinolytic system in pathologies such as metastatic cancer, parasitic infections, hemophilia and other hemorrhagic syndromes, in which an intense fibrinolytic activity is observed.

A new Kunitz-type plasmin inhibitor from scorpion venom.

Kunitz-type peptides from venomous animals are an important source of lead drug candidates towards human plasmin, a target of protease-associated diseases. However, no Kunitz-type plasmin inhibitor from venomous scorpion has been characterized. Here, we first investigated plasmin inhibiting activities of eight known Kunitz-type scorpion toxins Hg1, BmKTT-1, BmKTT-2, BmKTT-3, LmKTT-1a, LmKTT-1b, LmKTT-1c and BmKPI, and found a new plasmin inhibitor BmKTT-2, a Kunitz-type toxin peptide from the scorpion Buthus martensi karch. Protease inhibitory activity assay showed that BmKTT-2 potently inhibited plasmin with a Ki value of 8.75 ± 2.05 nM. Structure-function relationship studies between BmKTT-2 and plasmin showed that BmKTT-2 is a classical Kunitz-type plasmin inhibitor: Lys13 in BmKTT-2 is the P1 site, and Ala14 in BmKTT-2 is the P1' site. Interestingly, BmKTT-2 has potent inhibiting activities towards three important digestive serine proteases trypsin, chymotrypsin and elastase, suggesting a good stability for administering oral medications. To the best of our knowledge, BmKTT-2 is the first Kunitz-type human plasmin inhibitor from scorpion venom, providing novel insights into drug developments targeting human plasmin protease.

Inhibitors of melanogenesis in B16 melanoma 4A5 cells from flower buds of Lawsonia inermis (Henna).

The methanolic extract of Lawsonia inermis L. (henna) showed significant inhibitory activity toward melanogenesis in B16 melanoma 4A5 cells. Among the constituents isolated from the methanolic extract, luteolin, quercetin, and (±)-eriodictyol showed stronger inhibitory activity than the reference compound, arbutin. Several structure-activity relationships of the flavonoids were suggested, and OGlc

Bioassay-guided isolation and identification of anti-platelet-active compounds from the root of Ashitaba (Angelica keiskei Koidz.).

Platelet aggregation is fundamental to a wide range of physiological and pathological processes, including the induction of thrombosis and arteriosclerosis. Anti-platelet activity of a crude methanol extract and solvent fractions of Ashitaba roots (Angelica keiskei Koidz.) was evaluated using a turbidimetric method using washed rabbit platelets. We identified the anti-platelet activities of two chalcones, 4-hydroxyderricin and xanthoangelol, isolated from the ethyl acetate-soluble fraction of Ashitaba roots by using a bioassay-guided isolation method. 4-Hydroxyderricin and xanthoangelol effectively inhibited platelet aggregation induced by collagen (IC50 of 41.9 and 35.9 µM, respectively), platelet-activating factor (IC50 of 46.1 and 42.3 µM, respectively) and phorbol 12-myristate 13-acetate (IC50 of 16.5 and 45.9 µM, respectively). These compounds did not inhibit thrombin-induced platelet aggregation (IC50 of>80 µM). The results suggest that the chalcones 4-hydroxyderricin and xanthoangelol may be potent anti-thrombotic components of A. keiskei Koidz.

[On the history of vitamin K, dicoumarol and warfarin]. / Pionerer bag vitamin K, dikumarol og warfarin.

The history of the discovery and development of vitamin K and its antagonists, the oral anticoagulants dicoumarol and warfarin, are fascinating, triumphant landmarks in the annals of medicine. Vitamin K was found by Carl Peter Henrik Dam and Fritz Schønheyder from the University of Copenhagen. The discovery was initiated by Dam, by a lucky choice of chicks in the dissertation of sterol metabolism, since the vitamin is not formed by intestinal bacteria in these animals. In these experiments the lack of an unknown factor in the synthetic diet caused internal bleeding similar to that found in scurvy, but the bleeding was not reversed by vitamin C and it could not be explained by the lack of classical vitamins. In 1935 the unknown antihaemorrhagic factor was named vitamin K and a few months later the phenomenon was also observed by H.J. Almquist and E.L.R. Stokstad in Berkeley. The activity of the factor was determined by bioassay in different extracts of green vegetables and alfalfa by Dam and Schønheyder. Vitamin K was isolated in 1939 by Dam and Paul Karrer in Zurich and the structure was determined by Edward Adelbert Doisy. Dam and Doisy were awarded the Nobel Prize in 1943. A dramatic story starts the discovery of dicoumarol. In the 1920s cattle in Canada began dying of internal bleeding with no obvious precipitating cause. Frank W. Schofield, a veterinary pathologist in Alberta, found that the mysterious disease was connected to the consumption of spoiled sweet clover hay and noted a prolonged clotting time. Ten years after a farmer traveled in a blizzard with his dead cow and a milk can of the unclotted blood to the University of Wisconsin. Only the door to the biochemical department of Karl Paul Link was open. This event started the isolation of the anticoagulant agent dicou- marol which was formed by microbial induced oxidation of coumarin in the mouldy sweet clover hay. More than hundred dicoumarol-like anticoagulants were synthesized by Link and his co-workers. A potent hemorrhagic agent named warfarin was first used as an effective rat poison. However, warfarin became the drug of choice and the break- through in the treatment of thromboembolic diseases. Today new oral anticoagulants are competing with warfarin.

Antifibrinolytic role of a bee venom serine protease inhibitor that acts as a plasmin inhibitor.

Bee venom is a rich source of pharmacologically active substances. In this study, we identified a bumblebee (Bombus ignitus) venom Kunitz-type serine protease inhibitor (Bi-KTI) that acts as a plasmin inhibitor. Bi-KTI showed no detectable inhibitory effect on factor Xa, thrombin, or tissue plasminogen activator. In contrast, Bi-KTI strongly inhibited plasmin, indicating that it acts as an antifibrinolytic agent; however, this inhibitory ability was two-fold weaker than that of aprotinin. The fibrin(ogen)olytic activities of B. ignitus venom serine protease (Bi-VSP) and plasmin in the presence of Bi-KTI indicate that Bi-KTI targets plasmin more specifically than Bi-VSP. These findings demonstrate a novel mechanism by which bumblebee venom affects the hemostatic system through the antifibrinolytic activity of Bi-KTI and through Bi-VSP-mediated fibrin(ogen)olytic activities, raising interest in Bi-KTI and Bi-VSP as potential clinical agents.

Discreplasminin, a plasmin inhibitor isolated from Tityus discrepans scorpion venom.

Tityus discrepans venom (TdV) produces digestive hemorrhages, disseminated intravascular coagulation, alveoli fibrin deposition and/or prothrombin and partial thromboplastin time alterations in humans. T. discrepans venom presents an in vitro tissue plasminogen activator-like (tPA-like), fibrino(geno)lytic and plasmin inhibitory activities. The plasmin inhibitor, called discreplasminin, was isolated from TdV. Discreplasminin has a pI of 8.0 and a relative molecular weight of <6,000 Da. Discreplasminin and aprotinin strongly inhibited plasmin activity and moderately tPA activity, while epsilon amino caproic acid (EACA) moderately inhibited both enzymes. In presence and absence of fibrin, the plasmin generation by tPA was completely inhibited by aprotinin and discreplasminin. EACA in the absence of fibrin partially inhibited plasmin generation (37%); however, it produced a total inhibition of plasmin generation on a fibrin surface. The tPA-clot lysis assay showed that discreplasminin acts like aprotinin inducing a slight delay in lysis time and lysis rate; in contrast, EACA presented a total inhibitory effect on fibrin lysis. These results suggest that discreplasminin presents an anti-fibrinolytic mechanism similar to aprotinin. Discreplasminin probably interacts with the active sites of plasmin and tPA. The presence of discreplasminin and other similar components in scorpion venom could partially explain the generalized fibrin deposition which was found previously in rams.

Thrombin activatable fibrinolysis inhibitor and an antifibrinolytic pathway.

Coagulation and fibrinolysis are processes that form and dissolve fibrin, respectively. These processes are exquisitely regulated and protect the organism from excessive blood loss or excessive fibrin deposition. Regulation of these cascades is accomplished by a variety of mechanisms involving cellular responses, flow, and protein-protein interactions. With respect to regulation mediated by protein-protein interaction, the coagulation cascade appears to be more complex than the fibrinolytic cascade because it has more components. Yet each cascade is regulated by initiators, cofactors, feedback reactions, and inhibitors. Coagulation is also controlled by an anticoagulant pathway composed of (minimally) thrombin, thrombomodulin, and protein C.(1) Protein C is converted by the thrombin/thrombomodulin complex to activated protein C (APC), which catalyzes the proteolytic inactivation of the essential cofactors required for thrombin formation, factors Va and VIIIa. An analogous antifibrinolytic pathway has been identified recently. This pathway provides an apparent symmetry between coagulation and fibrinolysis and is also composed of thrombin, thrombomodulin, and a zymogen that is activated to an enzyme. The enzyme proteolytically inactivates a cofactor to attenuate fibrinolysis. However, unlike APC, which is a serine protease, the antifibrinolytic enzyme is a metalloprotease that exhibits carboxypeptidase B-like activity. Within a few years of each other, 5 groups independently described a molecule that accounts for this antifibrinolytic activity. We refer to this molecule as thrombin activatable fibrinolysis inhibitor (TAFI), a name that is based on functional properties by which it was identified, assayed, and purified. (Because of the preferences of some journals "activatable" is occasionally referred to as "activable.") This review will encompass a historical account of efforts to isolate TAFI and characterize it with respect to its activation, activity, regulation, and potential function in vivo.

Identification of an inhibitor of tissue-type plasminogen activator-mediated fibrinolysis in human neutrophils. A role for defensin.

An inhibitor of tissue-type plasminogen activator (tPA)-mediated and plasminogen-dependent fibrinolysis was isolated from human neutrophils. On a G-50 gel filtration column, the antifibrinolytic activity present in neutrophil homogenates comigrated with proteins of < 13 kDa. The inhibitory fraction had only a slight effect on urokinase with plasminogen- or plasmin-mediated fibrinolysis and no effect on urokinase- or plasmin-mediated cleavage of H-D-valyl-L-leucyl-L-lysine-p-nitroanilide (S-2251). The neutrophil-derived fraction inhibited tPA with plasminogen activity on S-2251 but not on H-D-isoleucyl-L-prolyl-L-arginine-p-nitroanilide (S-2288). The inhibition of tPA-mediated and plasminogen-dependent fibrinolysis or S-2251 cleavage showed a competitive pattern and could be relieved by increasing the concentration of plasminogen. The same fraction also inhibited binding of plasminogen to fibrin. Consecutive purification steps revealed that the molecular mass of the inhibitor was 1-5-kDa. Polylysine-Sepharose affinity chromatography indicated that the inhibitor is a protein of 4 kDa, migrating as one band on SDS-polyacrylamide gel electrophoresis. Amino acid sequence analysis of this band showed the presence of two sequences, differing by one amino acid, which are identical to defensin I and II. Comparison of the sequences of plasminogen and defensin showed homology of defensin to the plasminogen kringles known to contain the lysine binding sites. The close structural similarity between defensin and plasminogen kringles and the ability of defensin to compete with plasminogen on binding to fibrin explain the ability of defensin to inhibit tPA-mediated, plasminogen-dependent fibrinolysis. These results suggest that the antifibrinolytic activity of defensin may have a biological function in preventing the spread of infection.

Deficient antithrombin III activity and enhanced fibrinolysis in patients with liver disease: evidence against a cause-effect relationship.

To investigate the pathogenesis of fibrinolysis in liver disease, antithrombin III (AT III) activity, prothrombin fragment (F1 + 2) and d-dimer (D-DI) were measured in 50 patients with liver disease and in 17 healthy controls. Moreover, 4 patients with cirrhosis were randomly assigned to receive either an intravenous infusion of AT III (at two different dosages) or placebo, with a crossover design. Increased levels of D-DI were detected in patients with cirrhosis and hepatocellular carcinoma in comparison both with control subjects and with patients with acute hepatitis or mild chronic liver disease. An inverse correlation was observed between AT III and D-DI (r = -0.755, P < 0.001, simple linear regression), while no correlation was found between D-DI or AT III and F1 + 2. The correlation of the deficiency of AT III activity by infusion of human AT III did not result in any significant change (P0.10, analysis of variance for repeated measures) of the plasma concentration of either D-DI or F1 + 2, in comparison to placebo. Thus, advanced forms of chronic liver disease, but not acute hepatitis and mild forms of chronic liver disease, are associated with increased plasma concentrations of markers of fibrinolysis, which are inversely correlated with AT III activity. However, the correction of the deficient AT III activity does not affect the plasma concentration of either D-DI or F1 + 2, thence not supporting the hypothesis that enhanced fibrinolysis in advanced liver disease is the result of low-grade disseminated intravascular coagulation.

[The antifibrinolytic action of the D-dimer fragment]. / Antifibrinoliticheskoe deistvie fragmenta D-dimera.

The effect of D-dimer on the process of plasmin hydrolysis of unstabilized and crosslinked fibrin has been studied. Less degraded early, intermediate, and late products of fibrin cleavage have been revealed by electrophoresis of reduced and nonreduced samples. The molecular mechanism of antifibrinolytic effect of the D-dimer is supposed to be determined by shielding of peptide regions of monomer fibrin, localized both in N-terminal area of beta chain and in alpha, beta, and gamma chains between D and E domains. A notion has been proposed of autoinhibition of fibrinolytic reaction as a phenomenon related to the physical-chemical regulation of fibrinogen transformation into fibrin.

Low molecular weight fibrinolytic inhibitor from Guerin epithelioma.

Antifibrinolytic activity of the extract from Guerin epithelioma, a highly metastatic tumour implanted to rats, was determined by fibrinolytic and zymographic methods. The extract exhibits antifibrinolytic activity which is thermostable (60-100 degrees C) and pH-stable (pH 2.7-12). It contains a fibrinolytic inhibitor, with Mr about 7000, with antiplasmin properties, bound to lys-Sepharose and heparin-Sepharose. The molecular weight, physicochemical properties and antiplasmin action of the epithelioma inhibitor prove its identity with the low molecular weight antifibrinolytic factor appearing in the plasma of rats during the development of this tumour.

Multiple molecular forms of acid-stable plasmin inhibitor derived from human urinary trypsin inhibitor.

It was found that cyanogen bromide (BrCN) treatment of the highly purified human urinary trypsin inhibitors (H-UTI; specific activity 1,897 U/mg protein, and L-UTI; specific activity 1,850 U/mg protein) readily produced new plasmin inhibitors with almost no loss of UTI activity. Five multiple forms of chemically cleaved inhibitors (UTIB-I, UTIB-II, UTIB-III, UTIB-IV and UTIB-V) could be isolated from BrCN-treated L-UTI by isoelectric focusing and gel filtration. These inhibitors were very acid-stable and their isoelectric points (pI) were 4.5, 4.6, 4.9, 5.1 and 6.4, respectively. The molecular weights by SDS-polyacrylamide gel electrophoresis were almost the same at about 23,000 +/- 3,000. Although these inhibitors showed both anti-plasmin and anti-trypsin activities, much higher anti-plasmin/anti-trypsin activities were observed in the cleaved inhibitors than in the parent UTI. They competitively inhibited human plasmin with Ki values of 3.0-4.1 X 10(-8) mol/l (H-D-Val-Leu-Lys-pNA substrate).

Partial characterization of a fibrinolytic inhibitor produced by cultured endothelial cells derived from human umbilical vein.

A preliminary characterization of a fibrinolytic inhibitor released by human umbilical vein endothelial cells in primary culture is reported. This molecule of Mr comprised between 2 X 10(5) and 10(6) and of alpha 2 mobility precipitates at 43% ammonium sulphate saturation and is totally adsorbed on Concanavalin A Sepharose 4 B. A possible relationship with alpha macroglobulins is discussed.

Low molecular weight trypsin-plasmin inhibitors isolated from papain treated urinary trypsin inhibitor.

Papain treatment of human urinary trypsin inhibitor (UTI67; mol. wt. 43,000 by SDS-polyacrylamide gel electrophoresis, specific activity 1,897 U/mg protein) produced four new protease inhibitors, which were highly purified by gel chromatography on Sephadex G-100 and isoelectric focusing. The purified inhibitors (UTI26, UTI9-I, UTI9-II, and UTI9-III) were shown to be homogeneous by polyacrylamide disc gel electrophoresis, and had apparent molecular weights of 26,000, 9,000, 9,000, and 9,800, respectively, by sodium dodecyl sulfate gel electrophoresis. During enzymatic degradation of UTI67, the amino acid compositions changed to more basic, and the isoelectric point increased from pH 2.0 (UTI67) to pHs 4.4, 5.2, 6.6, and 8.3 (UTI26, UTI9-I, UTI9-II, UTI9-III), respectively. Both the parent and degraded inhibitors had anti-plasmin activity as well as antitrypsin and anti-chrymotrypsin activities. Much higher anti-plasmin/anti-trypsin and anti-plasmin/anti-chymotryspin activities were observed in the degraded inhibitors than in the parent UTI67. They competitively inhibited human plasmin with Ki values of 1.13 X 10(-7) - 2.12 X 10(-6) M (H-D-Val-Leu-Lys-pNA substrate). The reactions were very fast and the active site of the inhibitors of plasmin was thought to be different from that to trypsin or chymotrypsin.