A novel serine protease from strawberry (Fragaria ananassa): Purification and biochemical characterization

A new trypsin inhibitor from Centrosema plumieri effective against digestive proteases from Tribolium castaneum, an eco-friendly alternative

Tribolium castaneum, also known as the red flour beetle, is a polyphagous pest that seriously damages agricultural products, including stored and processed grains. Researchers have aimed to discover alternative pest control mechanisms that are less harmful to the ecosystem than those currently used. We conduct the purification and characterization of a protease inhibitor from C. plumieri seeds and an in vitro evaluation of its insecticidal potential against the insect pest T. castaneum. The trypsin inhibitor was isolated from C. plumieri seeds in a single-step DEAE-Sepharose column chromatography and had a molecular mass of 50 kDA. When analyzed for interaction with different proteolytic enzymes, the inhibitor exhibited specificity against trypsin and no activity against other serine proteases such as chymotrypsin and elastase-2. The isolated inhibitor was able to inhibit digestive enzymes of T. castaneum from extracts of the intestine of this insect. Therefore, we conclude that the new protease inhibitor, specific in tryptic inhibition, of protein nature from the seeds of C. plumieri was effective in inhibiting the digestive enzymes of T. castaneum and is a promising candidate in the ecological control of pests.

Production of milk-coagulating protease by fungus Pleurotus djamor through solid state fermentation using wheat bran as the low-cost substrate

Proteases are enzymes that hydrolyze peptide bonds present in proteins and peptides. They are widely used for various industrial applications, such as in the detergent, food, and dairy industries. Cheese is one of the most important products of the dairy industry, and the coagulation stage is crucial during the cheese-making process. Enzymatic coagulation is the most common technique utilized for this purpose. Microbial enzymes are frequently used for coagulation due to their advantages in terms of availability, sustainability, quality control, product variety, and compliance with dietary and cultural/religious requirements. In the present study, we identified and subsequently characterized milk coagulant activity from the fungus Pleurotus djamor PLO13, obtained during a solid-state fermentation process, using the agro-industrial residue, wheat bran, as the fermentation medium. Maximum enzyme production and caseinolytic activity occurred 120 h after cultivation. When the enzyme activity against various protease-specific synthetic substrates and inhibitors was analyzed, the enzyme was found to be a serine protease, similar to elastase 2. This elastase-2-like serine protease was able to coagulate pasteurized whole and reconstituted skim milk highly efficiently in the presence and absence of calcium, even at room temperature. The coagulation process was influenced by factors such as temperature, time, and calcium concentration. We demonstrate here, for the first time, an elastase-2-like enzyme in a microorganism and its potential application in the food industry for cheese production.

Purification and characterization of a new trypsin-like protease from Crotalaria stipularia

Proteases are the main enzymes traded worldwide-comprising 60% of the total enzyme market-and are fundamental to the degradation and processing of proteins and peptides. Due to their high commercial demand and biological importance, there is a search for alternative sources of these enzymes. Crotalaria stipularia is highlighted for its agroecological applications, including organic fertilizers, nematode combat, and revegetation of areas contaminated with toxic substances. Considering the pronounced biotechnological functionality of the studied species and the necessity to discover alternative sources of proteases, we investigated the extraction, purification, and characterization of a protease from seeds of the C. stipularia plant. Protease isolation was achieved by three-phase partitioning and single-step molecular exclusion chromatography in Sephacryl S-100, with a final recovery of 47% of tryptic activity. The molecular mass of the isolated enzyme was 40 kDa, demonstrating optimal activities at pH 8.0 and 50 °C. Enzymatic characterization demonstrated that the protease can hydrolyze the specific trypsin substrate, BApNA. This trypsin-like protease had a Km, Vmax, Kcat, and catalytic efficiency constant of 0.01775 mg/mL, 0.1082 mM/min, 3.86 s-1, and 217.46, respectively.

Strawberry Protease as a Laundry Detergent Additive Candidate: Immobilization, Compatibility Study with Detergent Ingredients, and Washing Performance Test

The potential of strawberry-derived protease as a component of laundry detergent is investigated. The compatibility of the enzyme with various surfactants, oxidizing agents, and commercial detergents is tested. The immobilized enzyme prepared by immobilizing Co2+ ions together with the enzyme is also tested. Strawberry crude protease shows high stability in the presence of surfactants frequently used in detergents. The enzyme is found to be relatively stable to oxidizing agents. In addition, it is determined that strawberry protease works in excellent compatibility with different commercial solid and liquid detergents in the Turkish market and also maintains its stability very well. Washing tests based on visual examination also reveal that the enzyme improves the washing performance of the tested detergent. All these properties and high activity at alkaline pH make this enzyme a very strong candidate for use in laundry detergent formulations.

In-vitro anti-inflammatory activity of serine protease inhibitor from Cassia siamea and Dolichos biflorus: A comparative study

Cassia siamea is a nonedible legume belonging to Fabaceae. The seed of C. siamea contains ~16% of protein. The study reports the biochemical characterization of purified novel serine protease inhibitor from seeds of C. siamea, aimed with assessing the anti-inflammatory activity. The seed extract was subjected to ammonium sulfate precipitation followed by fast protein liquid chromatography (FPLC)-anion exchange chromatography and affinity-chromatography to obtain a relative pure protease inhibitor. Thirty-fivefold purification with the specific activity of 250 U/mg of trypsin inhibitory unit was obtained. The characterization of protease inhibitor for optimum temperature, pH, and metal ions were measured using N-α-benzoyl-DL-arginine-p-nitroanilide (BAPNA) assay and casein zymogram. The C. siamea trypsin inhibitor (CsTI) has a relative molecular mass of 25.540 kDa. Purified CsTI and Dolichos biflorus were tested for anti-inflammatory efficacy against A549 and RAW264.7 cell lines. The inhibitory activity of both purified inhibitors are comparable and are potent toward anti-inflammatory activity. The purified inhibitor shows to be a promising candidate as anti-inflammatory agent by targeting the serine proteases.

Novel recombinant keratin degrading subtilisin like serine alkaline protease from Bacillus cereus isolated from marine hydrothermal vent crabs

Microbial secondary metabolites from extreme environments like hydrothermal vents are a promising source for industrial applications. In our study the protease gene from Bacillus cereus obtained from shallow marine hydrothermal vents in the East China Sea was cloned, expressed and purified. The protein sequence of 38 kDa protease SLSP-k was retrieved from mass spectrometry and identified as a subtilisin serine proteinase. The novel SLSP-k is a monomeric protein with 38 amino acid signal peptides being active over wide pH (7-11) and temperature (40-80 °C) ranges, with maximal hydrolytic activities at pH 10 and at 50 °C temperature. The hydrolytic activity is stimulated by Ca2+, Co2+, Mn2+, and DTT. It is inhibited by Fe2+, Cd2+, Cu2+, EDTA, and PMSF. The SLSP-k is stable in anionic, non-anionic detergents, and solvents. The ability to degrade keratin in chicken feather and hair indicates that this enzyme is suitable for the degradation of poultry waste without the loss of nutritionally essential amino acids which otherwise are lost in hydrothermal processing. Therefore, the proteinase is efficient in environmental friendly bioconversion of animal waste into fertilizers or value added products such as secondary animal feedstuffs.

Microbial alkaline serine proteases: Production, properties and applications

Proteolytic enzymes hold a pivotal position in numerous industrial processes where hydrolysis of protein molecules is required under precise conditions. The emerging trend of biotechnological applications in recent years has witnessed a renewed interest in alkaline serine proteases extending their utility in detergent, leather, textile, food and pharmaceutical industries. A variety of microorganisms have been reported to produce alkaline serine proteases on a large scale, however, extensive research to find an alkaline serine protease with desirable characteristics such as significant catalytic efficiency, expanded stability and broad substrate specificity is still ongoing. Although submerged fermentation dominates the commercial enzyme production, recent reports have emphasized on solid state fermentation technology which can reduce major cost associated with the enzyme production. In the present review, recent research on alkaline serine proteases along with their novel properties and production using solid state fermentation have been discussed.

Anticoagulant and antiplatelet activities of novel serine protease purified from seeds of Cucumis maderaspatensis

In this study, we report the biochemical characterization of a novel serine protease from seeds of Cucumis maderaspatensis, aimed with assessing the anticoagulant and antiplatelet activities. The purified serine protease was obtained by subjecting the seed extract to ammonium sulphate precipitation followed by anion exchange and gel filtration chromatography. Twenty seven-fold purification with the specific activity of 884.2 U/mg of protease activity was obtained. The characterization of the novel protease enzyme activity for optimum temperature, pH and effect of different protease inhibitors and metal ions were measured using caseinolytic assay and casein zymogram. The relative molecular mass of the novel neutral serine protease (CmSP) is ~ 32 kDa. Its anticoagulant was determined by assessing the delay in plasma re-calcification time in both platelet-rich and platelet-poor plasma. The antiplatelet activity of serine protease was demonstrated by inhibition of agonists induced platelet aggregation; it was in the order of Epinephrine > Adenosine tri phosphate. Further studies would decipher the mechanism of action to understand its therapeutic potential as an antiplatelet and anticoagulant molecule.

Fragaria Genus: Chemical Composition and Biological Activities

The strawberries represent in our days one of the main fresh fruits consumed globally, inevitably leading to large amounts of by-products and wastes. Usually appreciated because of their specific flavor, the strawberries also possess biological properties, including antioxidant, antimicrobial, or anti-inflammatory effects. In spite of the wide spread of the Fragaria genus, few species represent the subject of the last decade scientific research. The main components identified in the Fragaria species are presented, as well as several biological properties, as emerging from the scientific papers published in the last decade.

A novel thiol-dependent serine protease from Neocosmospora sp. N1

Alkaline proteases have several industrial applications. In the present study, newly isolated Neocosmospora sp. N1 was screened as hyper producer of serine protease. A multimeric protease of the fungus was purified to homogeneity till 96.78 fold purification with 22.51% recovery. The homogeneity of purified enzyme was checked by native PAGE and its molecular weight was found to be 198.03 kDa by MALDI-TOF. On SDS-PAGE analysis, enzyme was found to be a hetero oligomer of 17.66 kDa and 20.89 kDa subunits. The purified enzyme showed maximum activity with casein as substrate at 60 °C and pH 8.5. The K_m and V_max values were found to be 0.015 mg/ml and 454.45 U/ml, respectively. The enzyme was completely inhibited by PMSF, while the activity was 40% enhanced using β-mercaptoethanol, suggesting that it is a thiol-dependent serine protease. The purified protease was active over an alkaline pH range from 7 to 12 and temperatures from 20 °C to 60 °C. The enzyme exhibited excellent stability, almost 100% towards organic solvents such as toluene, benzene and hexane, surfactants such as Triton X-100, Tween-20, Tween-80 and SDS, as well as commercial detergents. The significant properties of purified enzyme assure that it could be a potential candidate for commercial purposes.