Purification, biochemical characterization and fibrinolytic potential of proteases produced by bacteria of the genus Bacillus: a systematic literature review

Recovery and partial purification of fibrinolytic protease from Pleurotus ostreatus and P. eryngii and cytotoxic and antioxidant activity of their extracts

Mushrooms are a source of primary and secondary metabolites. Little is known about the most suitable conditions for production of mushrooms by submerged fermentation. This article reports antioxidant and cytotoxic assays, in addition to quantitatively evaluating the content of proteases with fibrinolytic action in the crude extracts of two species of edible mushrooms produced in different formulations, as well as evaluating the recovery of these enzymes by aqueous two-phase systems (ATPS). The mushrooms Pleurotus ostreatus and Pleurotus eryngii, at concentration of 100 µg/mL, displayed inhibition of DPPH and ABTS radicals below 50%. In the cytotoxicity test, the cells human fibroblast cell lines (MRC-5) showed cell viability greater than 80%. Concerning fibrinolytic activity, P. eryngii presented 226.47 ± 7.26 U/mL, therefore being more efficient than P. ostreatus (71.5 ± 0.56 U/mL). In the recovery of the P. eryngii extract by ATPS, the fibrinolytic protease was partitioned in the salt phase (30.25 U/mL). The molecular mass of the proteases was between 75 and 100 kDa. These results prove the low cytotoxicity of the extracts produced and that fermentation in supplemented malt broth favored the excretion of fibrinolytic proteases compared to the other evaluated media.

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.

Insight into the thrombolytic ability of an extracellular fibrinolytic enzyme from Bacillus amyloliquefaciens GXU-1 isolated from Sipunculus nudus

Bacterial fibrinolytic enzymes have an important role in thrombolytic therapy due to their ability to dissolve fibrin. Therefore, purification, characterization and activity determination are of prime importance for bacterial fibrinolytic enzymes. In the current study, marine Bacillus amyloliquefaciens was first screened from Sipunculus nudus living in the Beibu Gulf of China and denoted as Guangxi University-1 (GXU-1). Then, an extracellular fibrinolytic enzyme (FEB-1) was purified from GXU-1 using ammonium sulfate precipitation, hydrophobic chromatography and gel filtration chromatography. The specific activity of FEB-1 was determined to be as high as 6789.74 U/mg. The relative molecular weight of FEB-1 was measured as 30 kDa through SDS‒PAGE. The optimum in vitro fibrinolytic activity of FEB-1 was identified at 37 °C and pH = 8. Furthermore, the activity of FEB-1 can be well preserved at 20-45 °C and pH = 6.0 to 9.0. The combination analysis of SDS‒PAGE and the molecular docking calculation revealed that FEB-1 can cleave more Aα- and Bβ-chains of fibrinogen than γ-chain. It is noteworthy that FEB-1 is comparatively stable under human-body environmental conditions, indicating its potential application in thrombosis therapy.

Purification of fibrinolytic enzyme from Bacillus amyloliquefaciens GUTU06 and properties of the enzyme

A producing-fibrinolytic enzyme strain was isolated with high yield. The strain was identified as Bacillus amyloliquefaciens. B. amyloliquefaciens GUTU06 fibrinolytic enzyme was purified by acetone precipitation and reverse micelle. Acetone precipitation condition and reverse micelle condition were examined. Results showed that the total reverse micelle extraction efficiency was 64.49 % ± 1.6 %. The purification fold of the entire process reached 13.38. The optimum pH of purified enzyme is 5, and the optimum temperature is 45 °C. Fe3+ and K+ can enhance the fibrinolytic activity of the enzyme. Compared to commercial fibrinolytic enzymes such as urokinase and lumbrukinase, GUTU06 fibrinolytic enzymes have a lower pH optimal range and higher temperature stability. The molecular weight of the enzyme was approximately 28 kDa. Reverse micelle extraction with cetyl trimethylammonium bromide as a surfactant combined with acetone precipitation is suitable for separating and purifying fibrinolytic enzymes and a promising technique for obtaining active proteins.

Edible Mushrooms as Source of Fibrin(ogen)olytic Enzymes: Comparison between Four Cultivated Species

Cardiovascular diseases represent the main cause of death. A common feature of cardiovascular disease is thrombosis resulting from intravascular accumulation of fibrin. In the last years, several fibrinolytic enzymes have been discovered in many medicinal or edible mushrooms as potential new antithrombotic agents. This study aimed to compare the fibrin(ogen)olytic activity of crude extracts from the fruiting bodies of four cultivated edible mushrooms: Lentinula edodes, Pleurotus ostreatus, Pleurotus eryngii, and Agrocybe aegerita. Fibrin(ogen)olytic activity was assessed by fibrin plate, spectrophotometric assay and electrophoretic analysis (SDS-PAGE and zymography). The highest activity was detected for P. ostreatus followed by P. eryngii, L. edodes and A. aegerita. Results indicated that enzymes exhibited maximum activity at pH 6-7 and 30-40 °C, respectively. Enzyme activity was inhibited by serine and metalloprotease inhibitors. We proposed a new index called the Specific Fibrin(ogen)olytic Index (SFI), which allows specification of the proportion of the total proteolytic capacity due to the fibrin(ogen)olytic activity. These data suggest that the extracts from fruiting bodies or powdered mushrooms can be used as functional ingredients for the development of new functional foods that may act as thrombolytic agents responding, at the same time, to the increasing demand for safe, healthy and sustainable food.