Purification and characterization of a novel fibrinolytic enzyme from the polychaete, Neanthes japonica (Iznka)

Impact of Dietary Variations on Kuruma Shrimp (Penaeus japonicus) Assessed through Individual-Based Rearing and Insights into Individual Differences

This study developed an individual-rearing method to compare the effects of live feed (sandworms Perinereis aibuhitensis), formulated pellet diets, and a mixture of live feed and formula feed on the Kuruma shrimp Penaeus japonicus, aiming to minimize the influence of non-dietary factors on the growth of P. japonicus, like cannibalism. Results indicated that live feed, with its higher protein, essential amino acids, and fatty acid content, led to significantly better growth and feeding performance in P. japonicus (p < 0.05) compared to pellet diets. A mixed diet resulted in a lower average daily protein intake yet maintained a growth and feeding performance comparable to live feed. The intestinal microbiota of shrimp, dominated by Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria, showed significant shifts with diet changes. Specifically, formulated feed increased the relative abundance of Vibrio and Photobacterium while decreasing Shimia and Rhodobacterales (p < 0.05), and feeding live food resulted in a more complex and stable bacterial network. Notably, individual variances in growth and feeding were observed among shrimps, with some on formulated diets showing growth comparable to those on live feed. Each shrimp's final weight, specific growth rate, protein efficiency rate, and average daily food intake positively correlated with its initial body weight (p < 0.05), and daily intake varied cyclically with the molting cycle. These findings suggest that individual-rearing is an effective approach for detailed feed evaluation and monitoring in P. japonicus, contributing to improved feed selection, development, and feeding strategies.

Proteases, a powerful biochemical tool in the service of medicine, clinical and pharmaceutical

Proteases, enzymes that hydrolyze peptide bonds, have various applications in medicine, clinical applications, and pharmaceutical development. They are used in cancer treatment, wound debridement, contact lens cleaning, prion degradation, biofilm removal, and fibrinolytic agents. Proteases are also crucial in cardiovascular disease treatment, emphasizing the need for safe, affordable, and effective fibrinolytic drugs. Proteolytic enzymes and protease biosensors are increasingly used in diagnostic and therapeutic applications. Advanced technologies, such as nanomaterials-based sensors, are being developed to enhance the sensitivity, specificity, and versatility of protease biosensors. These biosensors are becoming effective tools for disease detection due to their precision and rapidity. They can detect extracellular and intracellular proteases, as well as fluorescence-based methods for real-time and label-free detection of virus-related proteases. The active utilization of proteolytic enzymatic biosensors is expected to expand significantly in biomedical research, in-vitro model systems, and drug development. We focused on journal articles and books published in English between 1982 and 2024 for this study.

Purification and Properties of a Plasmin-like Marine Protease from Clamworm (Perinereis aibuhitensis)

Marine organisms are a rich source of enzymes that exhibit excellent biological activity and a wide range of applications. However, there has been limited research on the proteases found in marine mudflat organisms. Based on this background, the marine fibrinolytic enzyme FELP, which was isolated and purified from clamworm (Perinereis aibuhitensis), has exhibited excellent fibrinolytic activity. We demonstrated the FELP with a purification of 10.61-fold by precipitation with ammonium sulfate, ion-exchange chromatography, and gel-filtration chromatography. SDS-PAGE, fibrin plate method, and LC-MS/MS indicated that the molecular weight of FELP is 28.9 kDa and identified FELP as a fibrinolytic enzyme-like protease. FELP displayed the maximum fibrinolytic activity at pH 9 (407 ± 16 mm2) and 50 °C (724 ± 27 mm2) and had excellent stability at pH 7-11 (50%) or 30-60 °C (60%), respectively. The three-dimensional structure of some amino acid residues of FELP was predicted with the SWISS-MODEL. The fibrinolytic and fibrinogenolytic assays showed that the enzyme possessed direct fibrinolytic activity and indirect fibrinolysis via the activation of plasminogen; it could preferentially degrade Aα-chains of fibrinogen, followed by Bβ- and γ-chains. Overall, the fibrinolytic enzyme was successfully purified from Perinereis aibuhitensis, a marine Annelida (phylum), with favorable stability that has strong fibrinolysis activity in vitro. Therefore, FELP appears to be a potent fibrinolytic enzyme with an application that deserves further investigation.

Cytotoxicity of alkaline serine protease (ASPNJ) on Jurkat cells and its correlation with changes in the expression of membrane-associated proteins

We aim to study the inhibitory effect of alkaline serine protease (ASPNJ) on lymphocytic leukemia Jurkat cells and its related mechanism through examining the expression of membrane proteins or membrane-associated proteins. MTT assay and trypan blue staining were used to detect the inhibitory effect of ASPNJ on the proliferation and growth of Jurkat cells. Wright-Giemsa staining was used to observe the effect of ASPNJ on the morphology of Jurkat cells. The effect of ASPNJ on Jurkat cell apoptosis was detected by flow cytometry. Two-dimensional electrophoresis-mass spectrometry (2-DE-MS) was used to detect and identify the differentially expressed proteins of Jurkat cells treated with ASPNJ (4 μg/mL, 3 h), of which three were selected and verified by Western blot. ASPNJ significantly inhibited the proliferation of leukemia cells (Raji, U937, and Jurkat), caused obvious morphological changes, and induced apoptosis of Jurkat cells. ASPNJ also increased the sensitivity of Jurkat cells to vincristine (VCR). Seven differentially expressed proteins were obtained through 2DE-MS, of which Peroxiredoxin-6 (PRDX6), Calcium-binding protein (CHP1), and 40S ribosomal protein SA (RPSA) were validated. ASPNJ can cause significant toxic effects on Jurkat cells and enhance the effects of VCR. The mechanism of action of ASPNJ on Jurkat cells may be related to differentially expressed proteins such as PRDX6. This study provides a new experimental basis and direction for antileukemia research.

Antioxidant Activities of Aqueous Extracts and Protein Hydrolysates from Marine Worm Hechong (Tylorrhynchus heterochaeta)

Hechong (Tylorrhynchus heterochaeta) is an edible marine worm widely distributed in the estuary area. The objective of this study is to determine the antioxidant activities of extracts and protein hydrolysates from Hechong. Results showed that the aqueous extracts of steamed Hechong had the highest antioxidant values using the methods of DPPH, ABTS, and FRAP testing (76.29 μmol TE/g, 181.04 μmol TE/g, and 10.40 mmol Fe²⁺/100 g, respectively). Furthermore, protein hydrolysates of Hechong were observed significant antioxidant activities when compared to crude Hechong. The purification was carried out by DEAE-52 cellulose and Sephadex G-100 column chromatography. The microspatial structure of glycoprotein showed fibrous shapes and cracks with uniform distribution. The study has concluded that the extract and protein hydrolysates of Hechong have significant antioxidant activities, which is merited to be further investigated in the food and pharmaceutical fields.

Rapid Degradation of SARS-CoV-2 Spike S Protein by A Specific Serine Protease

The S protein of SARS-CoV-2 is a crucial structural and functional component for virus entry. Due to the constant mutation of the virus, there are very limited ways to prevent and control COVID-19. This experiment used a macroscopic SDS-PAGE method and proved that the S protein of wild-type SARS-CoV-2 virus, especially the S1 subunit, is very sensitive to alkaline serine protease with acidic pI (ASPNJ), NJ represents Neanthes japonica (Izuka) from which ASP is purified). ASPNJ cleaves proteins when the carbonyl group of the peptide bond is contributed by arginine or lysine. ASPNJ can degrade the S protein very quickly and effectively in vitro with relative selectivity. It can be inferred that the S, S1 and RBD of SARS-CoV-2 variants can also be easily degraded by ASPNJ. This rapid and strong degradation of the S protein by ASPNJ may become a potential new treatment strategy.

Purification and Characterization of a Thrombolytic Enzyme Produced by a New Strain of Bacillus subtil

Fibrinolytic enzymes with a direct mechanism of action and safer properties are currently requested for thrombolytic therapy. This paper reports on a new enzyme capable of degrading blood clots directly without impairing blood coagulation. This enzyme is also non-cytotoxic and constitutes an alternative to other thrombolytic enzymes known to cause undesired side effects. Twenty-four Bacillus isolates were screened for production of fibrinolytic enzymes using a fibrin agar plate. Based on produced activity, isolate S127e was selected and identified as B. subtilis using the 16S rDNA gene sequence. This strain is of biotechnological interest for producing high fibrinolytic yield and consequently has potential in the industrial field. The purified fibrinolytic enzyme has a molecular mass of 27.3 kDa, a predicted pI of 6.6, and a maximal affinity for Ala-Ala-Pro-Phe. This enzyme was almost completely inhibited by chymostatin with optimal activity at 48°C and pH 7. Specific subtilisin features were found in the gene sequence, indicating that this enzyme belongs to the BPN group of the S8 subtilisin family and was assigned as AprE127. This subtilisin increased thromboplastin time by 3.7% (37.6 to 39 s) and prothrombin time by 3.2% (12.6 to 13 s), both within normal ranges. In a whole blood euglobulin assay, this enzyme did not impair coagulation but reduced lysis time significantly. Moreover, in an in vitro assay, AprE127 completely dissolved a thrombus of about 1 cc within 50 min and, in vivo, reduced a thrombus prompted in a rat tail by 11.4% in 24 h compared to non-treated animals.

Purification and Characterization of a Novel Fibrinolytic Enzyme from Cipangopaludina Cahayensis

Background:

Cipangopaludina cahayensis contains active fibrinolytic proteins and has been considered a potential anti-cancer agent. However, its anti-cancer characteristics and functions have yet to be elucidated

Objectives:

To study the fibrinolytic activity and anticancer activity of crude protein extracts from Cipangopaludina cahayensis.

Materials and Methods:

Crude proteases were separated and extracted from the Cipangopaludina cahayensis through homogenization, desalting, ammonium sulfate fractionation, dialysis, and ion exchange chromatography. The fibrinolytic activity of extracted proteins was assessed using the fiber plate method. Total protein concentrations of the crude proteases were determined via BCA assay. Molecular weights (MWs) were determined through SDS-PAGE electrophoresis.

Results:

The crude extract had a MW of ~ 50 kDa, and the highest protein concentration was 3.026 mg.mL^-1. The optimum pH for fibrinolytic activity was 7.0. Cell culture assays demonstrated that the addition of the crude enzyme extracts to the human ovary cancer cell line Ovcar-3 resulted in significant growth defects.

Conclusions:

Our data showed that crude proteins purified from Cipangopaludina cahayensis are novel fibrinolytic proteases and have potential anti-cancer propertie

A critical review on marine serine protease and its inhibitors: A new wave of drugs?

Marine organisms are rich sources of enzymes and their inhibitors having enormous therapeutic potential. Among different proteolytic enzymes, serine proteases, which can be obtained from various marine organisms show a potential to biomedical application as thrombolytic agents. Although this type of proteases plays a crucial role in almost all biological processes, their uncontrolled activity often leads to several diseases. Accordingly, the actions of these types of proteases are regulated by serine protease inhibitors (SPIs). Marine SPIs control complement activation and various other physiological functions, such as inflammation, immune function, fibrinolysis, blood clotting, and cancer metastasis. This review highlights the potential use of serine proteases and their inhibitors as the new wave of promising drugs.

A novel serine protease with anticoagulant and fibrinolytic activities from the fruiting bodies of mushroom Agrocybe aegerita

A novel fibrinolytic enzyme, ACase was isolated from fruiting bodies of a mushroom, Agrocybe aegerita. ACase was purified by using ammonium sulfate precipitation, gel filtration, ion exchange and hydrophobic chromatographies to 237.12 fold with a specific activity of 1716.77 U/mg. ACase was found to be a heterodimer with molecular mass of 31.4 and 21.2 kDa by SDS-PAGE and appeared as a single band on Native-PAGE and fibrin-zymogram. The N-terminal sequence of the two subunits of ACase was AIVTQTNAPWGL (subunit 1) and SNADGNGHGTHV (subunit 2). ACase had maximal activity at 47 °C and pH 7.6. It's activity was improved by Cu²⁺, Na⁺, Fe³⁺, Zn²⁺, Ba²⁺, K⁺ and Mn²⁺, but inhibited by Fe²⁺, Mg²⁺ and Ca²⁺. PMSF, SBTI, aprotinine and Lys inhibited the enzyme activity, which suggested that ACase was a serine protease. ACase could degrade all three chains (α, β and γ) of fibrinogen. Moreover, the enzyme acted as both, a plasmin-like fibrinolytic enzyme and a plasminogen activator. It could hydrolyze human thrombin slightly, which indicated that the ACase could inhibit the activity of thrombin and acted as an anticoagulant to prevent thrombosis. Based on these results, ACase might act as a therapeutic agent for treating thrombosis, or as a functional food. Further investigation of the enzyme is underway.

Characterization of an Intracellular Alkaline Serine Protease from Bacillus velezensis SW5 with Fibrinolytic Activity

ISP-SW5 is an intracellular alkaline serine protease gene from Bacillus velezensis SW5 that was heterologously expressed in Escherichia coli BL21 (DE3). Sequence analysis indicated that the ISP-SW5 gene has 960 bp open reading frame and encodes a protein of 319 amino acid residues. Three-dimensional structure of ISP-SW5 with the fibrinolytic activity from Bacillus velezensis was predicted by in silico analysis. Gly219 was the most likely active site for the fibrinolytic activity of ISP-SW5. The recombinant enzyme ISP-SW5 was purified by Ni-NTA Superflow Column. SDS-PAGE showed that this enzyme had a molecular mass of 34 kDa. The result of native-PAGE and N-terminal sequencing showed that the N-terminal propeptide of ISP-SW5 was cleaved during the maturation of protease. The optimum pH and temperature were 8.0 and 40 °C, respectively. Enzyme activity was markedly inhibited by PMSF and EDTA but enhanced by 5 mM Ca²⁺ and 2 mM Zn²⁺ by up to 143% and 115%, respectively. Additionally, ISP-SW5 retained 93%, 78%, and 49% relative enzyme activity after incubation with 0.5 M, 1 M and 2 M NaCl, respectively, at 4 °C for 12 h. The enzyme activity determined by casein as substrate was 1261 U/mg. ISP-SW5 could degrade fibrin at an activity of 3428 U/mg, and its properties reflect its potential application in developing a novel biological catalyst for efficient fibrin hydrolysis in medical treatment.

Purification, biochemical, and thermal properties of fibrinolytic enzyme secreted by Bacillus cereus SRM-001

The discovery of microbial fibrinolytic enzymes is essential to treat cardiovascular diseases. This study reports the discovery of a fibrinolytic enzyme secreted by Bacillus cereus SRM-001, a microorganism isolated from the soil of a chicken waste-dump yard. The B. cereus SRM-001 was cultured and the secreted fibrinolytic enzyme purified to show that it is a ∼28 kDa protein. The purified enzyme was characterized for its kinetics, biochemical and thermal properties to show that it possesses properties similar to plasmin. A HPLC-MS/MS analysis of trypsin digested protein indicated that the fibrinolytic enzyme shared close sequence homology with serine proteases reported for other Bacillus sp. The results show that the B. cereus SRM-001 secreted enzyme is a ∼28 kDa serine protease that possesses fibrinolytic potential.

Purification of serine protease from polychaeta, Lumbrineris nipponica, and assessment of its fibrinolytic activity

Ischemic stroke and cardiovascular disease can occur from blockage of blood vessels by fibrin clots formed naturally in the body. Therapeutic drugs of anticoagulant or thrombolytic agents have been studied; however, various problems have been reported such as side effects and low efficacy. Thus, development of new candidates that are more effective and safe is necessary. The objective of this study is to evaluate fibrinolytic activity, anti-coagulation, and characterization of serine protease purified from Lumbrineris nipponica, polychaeta, for new thrombolytic agents. In the present study, we isolated and identified a new fibrinolytic serine protease from L. nipponica. The N-terminal sequence of the identified serine protease was EAMMDLADQLEQSLN, which is not homologous with any known serine protease. The size of the purified serine protease was 28 kDa, and the protein purification yield was 12.7%. The optimal enzyme activity was observed at 50°C and pH 2.0. A fibrin plate assay confirmed that indirect fibrinolytic activity of the purified serine protease was higher than that of urokinase-PA, whereas direct fibrinolytic activity, which causes bleeding side effects, was relatively low. The serine protease did not induce any cytotoxicity toward the endothelial cell line. In addition, anticoagulant activity was verified by an in vivo DVT animal model system. These results suggest that serine protease purified from L. nipponica has the potential to be an alternative fibrinolytic agent for the treatment of thrombosis and use in various biomedical applications.

Purification and characterization of a novel fibrinolytic enzyme from Whitmania pigra Whitman

A fibrinolytic enzyme was purified from the dry body of Whitmania pigra Whitman. The fibrinolytic enzyme was purified to homogeneity with a yield of 0.003% and a purification of 630.7 fold. The molecular weight of the enzyme was estimated to be 26.7 kDa by reduced sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme was tested by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) and it showed that the enzyme was a novel fibrinolytic enzyme. The optimal pH and temperature of the enzyme were 8.5 and 55°C, respectively. Enzyme activity was enhanced by Na⁺, Mg^2+, and K⁺. On the contrary, the proteolytic activity was significantly inhibited by Mn²⁺, Fe²⁺, Fe³⁺, ethylenediaminetetraacetic acid (EDTA), and ethylenebis(oxyethylenenitrilo)tetraacetic acid (EGTA). Fibrinolytic and fibrinogenolytic assays showed that the enzyme preferentially hydrolyzed fibrinogen Aα-chains, followed by Bβ- and γ-chains. The α-, β-, and γ-γ-chains of fibrin were also degraded by the enzyme.

Potential fibrinolytic activity of an endophytic Lasiodiplodia pseudotheobromae species

Cost-effective, fibrinolytic agents possessing least or no antigenic properties are much in demand for their prospective use as clot busters in thrombolytic therapy. The present communication explores the potential of 22 endophytic Botryosphaeria species isolated from stem of Aegle marmelos for their fibrinolytic potential. Only nine fungal isolates exhibited proteolytic activity out of which only four possessed plasminogen-independent fibrinolytic activity. The endophytic fungal isolate #1088 AMSTITYEL showed maximum in vitro proteolytic and fibrinolytic activity with a halo formation of 153.86 and 113.04 mm², respectively. The partially purified protein exhibited a fibrinolytic activity equivalent to 6.51 U/ml of plasmin. SDS-PAGE of the dialysed fraction of #1088 AMSTITYEL resolved into six bands ranging from 26 to 80 kDa. Fibrin zymogram exhibited that a single band of molecular size ~80 KDa possessing the fibrinolytic activity. Furthermore, the bioactive isolate #1088 AMSTITYEL was identified as Lasiodiplodia pseudotheobromae using classical and molecular taxonomic tools.

A fibrinolytic protease AfeE from Streptomyces sp. CC5, with potent thrombolytic activity in a mouse model

Fibrinolytic proteases have potential applications in cardiovascular disease therapy. A novel fibrinolytic protease, AfeE, with strong thrombolytic activity was purified from Streptomyces sp. CC5. AfeE displayed maximum activity at 40°C in the pH range of 7.0-12.0. It was strongly inhibited by serine protease inhibitor phenylmethanesulfonylfluoride, soybean trypsin inhibitor, tosyl-l-lysine chloromethyl ketone and tosyl-l-phenylalanine chloromethyl ketone. The activity of the enzyme was partially inhibited by Cu(2+), Co(2+) and Zn(2+). AfeE exhibited higher substrate specificity for fibrin than fibrinogen, which has rarely been reported in fibrinolytic enzymes. AfeE also showed high thrombolytic activity in a carrageenan-induced mouse tail thrombosis model. AfeE prolonged prothrombin time, activated partial thromboplastin time, and thrombin time in rat blood. A bleeding time assay revealed that AfeE did not prolong bleeding time in mice at a dose of 1mg/kg. No acute cytotoxicity was observed for AfeE at 320μg/well in human umbilical vein endothelial cells. The afeE gene was cloned from the genome of Streptomyces sp. CC5. Full-length AFE-CC5E contained 434 amino acids and was processed into a mature form consisting 284 amino acids by posttranslational modification, as revealed by high-resolution mass spectrometry analysis. These results indicate that AfeE is a prospective candidate for antithrombotic drug development.

Statistical Optimization of Media Components for Production of Fibrinolytic Alkaline Metalloproteases from Xenorhabdus indica KB-3

Xenorhabdus indica KB-3, a well-known protease producer, was isolated from its entomopathogenic nematode symbiont Steinernema thermophilum. Since medium constituents are critical to the protease production, the chemical components of the selected medium (soya casein digest broth) were optimized by rotatable central composite design (RCCD) using response surface methodology (RSM). The effects of all five chemical components (considered as independent variables), namely tryptone, soya peptone, dextrose, NaCl, and dipotassium phosphate, on protease production (dependent variable) were studied, and it was found that tryptone and dextrose had maximum influence on protease production. The protease production was increased significantly by 66.31% under optimal medium conditions (tryptone—5.71, soya peptone—4.9, dextrose—1.45, NaCl—6.08, and dipotassium phosphate—0.47 in g/L). To best of knowledge, there are no reports on optimization of medium component for protease production by X. indica KB-3 using RSM and their application in fibrinolysis. This study will be useful for industrial processes for production of protease enzyme from X. indica KB-3 for its application in the field of agriculture and medicine.

Ultrasound assisted three phase partitioning of a fibrinolytic enzyme

The present investigation is aimed at ultrasound assisted three phase partitioning (UATPP) of a fibrinolytic enzyme from Bacillus sphaericus MTCC 3672. Three phase partitioning integrates the concentration and partial purification step of downstream processing of a biomolecule. Three phase system is formed with simultaneous addition of ammonium sulfate to crude broth and followed by t-butanol. UATPP of a fibrinolytic enzyme was studied by varying different process parameters such as ammonium sulfate saturation concentration, pH, broth to t-butanol ratio, temperature, ultrasound frequency, ultrasonication power, and duty cycle. The optimized parameters yielding maximum purity of 16.15-fold of fibrinolytic enzyme with 65% recovery comprised of 80% ammonium sulfate saturation, pH 9, temperature 30 °C, broth to t-butanol ratio 0.5 (v/v), at 25 kHz frequency and 150 W ultrasonication power with 40% duty cycle for 5 min irradiation time. SDS PAGE analysis of partitioned enzyme shows partial purification with a molecular weight in the range of 55-70 kDa. Enhanced mass transfer of UATPP resulted in higher fold purity of fibrinolytic enzyme with reduced time of operation from 1 h to 5 min as compared to conventional TPP. Outcome of our findings highlighted the use of UATPP as an efficient biosepartion technique.

Non-covalent modification of thrombolytic agent nattokinase: simultaneous improvement of fibrinolysis activity and enzymatic stability

Folic acid modified chitosan (CS-FA) was synthesized and applied to modify Nattokinase (NK), a thrombolytic agent, for better fibrinolysis activity and stability. It provides great opportunities in curing cardiovascular disease (CVD), a leading cause of death globally.

Biochemical characteristics of a fibrinolytic enzyme purified from a marine bacterium, Bacillus subtilis HQS-3

A fibrinolytic enzyme isolated from marine Bacillus subtilis HQS-3 was purified to electrophoretic homogeneity using ammonium sulphate precipitation, alkaline solution treatment, membrane concentration, dialysis, ion exchange, and gel filtration chromatography. SDS-PAGE and gel filtration chromatography showed that it was a monomeric protein with an apparent molecular weight of 26 kDa. The purified enzyme was active at pH 6.0-10.0 with an optimum pH of 8.0. It was stable at temperatures ranging from 25 to 37 °C, exhibiting maximum activity between 45 °C and 50 °C. The isoelectric point of the enzyme was 9.0-9.2, which was higher than those of other known fibrinolytic enzymes from Bacillus species. PMSF, EDTA, Cu(2+), Zn(2+), and Co(2+) inhibited the enzyme activity significantly. This enzyme did not cause hemolysis in vitro and preferred direct degradation of fibrin in the following order: α, β, and γ-γ chains. Thus, these results suggest that the marine-derived enzyme is a plasmin-like serine metalloprotease, which is distinct from other fibrinolytic enzymes from genus Bacillus.

Purification and characterization of a fibrinolytic enzyme from Streptomyces sp. XZNUM 00004

A fibrinolytic enzyme (SFE1) from Streptomyces sp. XZNUM 00004 was purified to electrophoretic homogeneity with the methods including ammonium sulfate precipitation, polyacrylamide gel, DEAE-Sepharose Fast Flow anion exchange and gel-filtration chromatography. The molecular weight of SFE1 was estimated to be 20 kDa by SDS-PAGE, fibrin zymography, and gel filtration chromatography. The isoelectric point was 4.9. K (m) and V (max) values were 0.96 mg/ml and 181.8 unit/ml, respectively. It was very stable at pH 5.0-8.0 and below 65 °C. The optimum pH for enzyme activity was 7.8. The optimum temperature was 35 °C. The fibrinolytic activity of SFE1 was enhanced by Na(+), K(+), Mn(2+), Mg(2+), Zn(2+) and Co(2+). Conversely, Cu(2+) showed strong inhibition. Furthermore, the fibrinolytic activity was strongly inhibited by PMSF, and partly inhibited by EDTA and EGTA. SFE1 rapidly hydrolyzed the Aα-chain of fibrinogen, followed by the Bβ-chain and finally the γ-chain. The first 15 amino acids of the N-terminal sequence were APITLSQGHVDVVDI. Additionally, SFE1 directly digested fibrin and not by plasminogen activators in vitro. SFE1 can be further developed as a potential candidate for thrombolytic therapy.

Purification and physicochemical characterization of a serine protease with fibrinolytic activity from latex of a medicinal herb Euphorbia hirta

A 34 kDa serine protease, designated as hirtin, with fibrinolytic activity was purified to homogeneity from the latex of Euphorbia hirta by the combination of ion exchange and gel filtration chromatography. The N-terminal sequence of hirtin was found to be YAVYIGLILETAA/NNE. Hirtin exhibited esterase and amidase activities along with azocaseinolytic, gelatinolytic, fibrinogenolytic and fibrinolytic activities. It preferentially hydrolyzed Aα and α-chains, followed by Bβ and β, and γ and γ-γ chains of fibrinogen and fibrin clot respectively. The optimum pH and temperature for enzyme activity was found to be pH 7.2 and 50 °C respectively. Enzymatic activity of hirtin was significantly inhibited by PMSF and AEBSF. It showed higher specificity for synthetic substrate p-tos-GPRNA for thrombin. The CD spectra of hirtin showed a high content of β-sheets as compared to α-helix. The results indicate that hirtin is a thrombin-like serine protease and may have potential industrial and therapeutic applications.

Bafibrinase: A non-toxic, non-hemorrhagic, direct-acting fibrinolytic serine protease from Bacillus sp. strain AS-S20-I exhibits in vivo anticoagulant activity and thrombolytic potency

A non-toxic, direct-acting fibrinolytic serine protease (Bafibrinase) demonstrating thrombolytic and anticoagulant properties was purified from Bacillus sp. strain AS-S20-I. Bafibrinase was monomeric, with a molecular mass of 32.3 kDa. The peptide mass fingerprinting of Bafibrinase revealed only 8.3% sequence coverage, suggesting it was a novel fibrinolytic enzyme. However, two of the tryptic digested de novo peptide sequences of Bafibrinase demonstrated good similarity with endopeptidases possessing serine in their catalytic triad. Further, catalytic activity of Bafibrinase was inhibited by serine protease inhibitor reinforcing this is a subtilisin-like serine protease. The apparent K(m) and V(max) values of Bafibrinase towards fibrin were determined as 0.24 μM and 2.8 μmol/min, respectively. It showed a K(m) value of 0.139 mM towards a chromogenic substrate for plasmin (D-Val-Leu-Lys-p-Nitroanilide dihydrochloride) and optimum activity at physiological conditions (37 °C and pH 7.4). Based on the cleavage pattern of fibrin and fibrinogen, Bafibrinase may be classified as an α,β-fibrinogenase. Bafibrinase could not degrade collagen and was non-cytotoxic to HT29 cells or mammalian erythrocytes. Further, Bafibrinase at a dose of 2 mg/kg was devoid of toxicity as well as hemorrhagic activity on BALB/c mouse model, supporting its suitability for the development of a better and safer thrombolytic drug. Bafibrinase was also superior to human plasmin in degrading in vitro thrombus. The in vivo anticoagulant nature of Bafibrinase is being explored for the treatment and prevention of thrombosis and other cardiovascular diseases.

Purification and characterization of a novel fibrinolytic enzyme from fruiting bodies of Korean Cordyceps militaris

A fibrinolytic enzyme has been purified from the fruiting bodies of Korean Cordyceps militaris. The molecular mass of the enzyme was estimated to be 34 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), fibrin-zymography, and gel filtration chromatography. The 15 amino acid residues of the N-terminal sequence of the enzyme were APVEQCDAPVGLARL, which is dissimilar to those of fibrinolytic enzymes from other mushrooms. Optimal pH and temperature values of the enzyme were 7.0 and 40°C, respectively. The enzyme activity was completely inhibited by phenylmethylsulfonyl fluoride (PMSF), TPCK, 1,10-phenanthroline, Cu(2+), and Ba(2+). It was also significantly inhibited by aprotinin, EDTA, and EGTA. The enzyme showed a higher specificity for a synthetic substrate, N-succinyl-Ala-Ala-Pro-Phe-p-nitroanilide, exhibiting that it is a chymotrypsin-like serine metalloprotease. The enzyme preferentially hydrolyzed the fibrinogen Aα-, followed by the Bβ-chains and the γ-chain. The α, β, and γ-γ chains of fibrin were also degraded by the enzyme.

A novel alkaline serine protease with fibrinolytic activity from the polychaete, Neanthes japonica

A new protease named NJP with fibrinolytic activity was isolated from Neanthes japonica (Izuka), by a combination of ammonium sulfate fractionation, hydrophobic chromatography, ion-exchange chromatography and gel filtration. The molecular mass of NJP was approximately 28.6-33.5kDa as estimated by MALDI-TOF mass spectrometry and SDS-PAGE, which revealed a monomeric form of the protease. The isoelectric point of NJP determined by 2-DE was 9.2. NJP was stable in the range of pH 7.0-11.0 with a maximum enzymatic activity at 40°C and pH 9.0. The hydrolyzing activity of NJP on fibrinogen started from the Aα-chain, followed by the Bβ-chain, and the γ-chain at last. NJP had also a higher specificity for the chromogenic substrate S-2238 for thrombin. NJP activity was completely inhibited by PMSF. Analysis of partial amino acid sequences showed that NJP had very low homology with other known fibrinolytic enzymes. These results indicate that NJP is a novel alkaline thrombin-like serine protease. Thus NJP may have potential applications in the prevention and treatment of thrombosis.

Neanthes japonica (Iznka) fibrinolytic enzyme reduced cerebral infarction, cerebral edema and increased antioxidation in rat models of focal cerebral ischemia

Thrombolytic agent is increasingly being used in treating acute ischemic stroke. A novel protease with strong thrombolytic activity, Neanthes japonica (Iznka) fibrinolytic enzyme (NJF) discovered in our laboratory has been reported with characteristics of direct hydrolyzing fibrin and fibrinogen. The neuroprotective effect of NJF and urokinase (UK) was tested in rat models of middle cerebral artery occlusion (MCAO). The model was successfully produced by introducing an intraluminal suture into the left middle cerebral artery (MCA). NJF (0.25, 0.5, 1mg/kg) was injected intravenously 1h after the onset of reperfusion. Compared with vehicle group, MCAO animals treated with NJF showed dose dependent reduction in cerebral infarction with improved neurological outcome. Meanwhile, ischemia induced cerebral edema was reduced in a dose dependent manner. Treatment with NJF at 0.5mg/kg was almost equivalent to UK at 15,000U/kg dosage in the reduction of cerebral infarction and cerebral edema. Biomedical assay showed that NJF treatment suppressed lipid peroxidation and restored superoxide dismutase (SOD) activities in brain tissue. These results suggest that NJF posses neuroprotective potential in rat MCAO and reperfusion model. Neuroprotection shown by NJF may be attributed to inhibition of lipid peroxidation, increase in endogenous antioxidant defense enzymes.