Benghalensin, a highly stable serine protease from the latex of medicinal plant Ficus benghalensis

Proteolytic Activity of Silkworm Thorn (Cudrania tricuspidata) Fruit for Enzymatic Hydrolysis of Food Proteins

This study aimed to isolate the proteolytic fraction from the silkworm thorn fruit (Cudrania tricuspidata) through ethanol precipitation at different ratios, and to determine its proteolytic activity and optimal activity conditions. Furthermore, the hydrolysis characteristics and antioxidant activity of soy protein isolate (SPI) and whey protein concentrate (WPC) hydrolyzates obtained through the enzymatic hydrolysis of freeze-dried silkworm thorn fruit powder (SF) were evaluated. For isolation and partial purification of proteolytic fraction, the water-solubilized fraction of the silkworm thorn fruit was purified through ethanol precipitation at four different ratios of 1:1, 1:2, 1:4, and 1:6 (v/v). The protein recovery rate, caseinolytic activity, protein pattern, and optimal activity (pH, temperature, and inhibitors) of fractional ethanol precipitate obtained from the silkworm thorn fruit (ESF) were evaluated. The proteolytic fraction obtained from silkworm thorn fruit exhibited a major protein band around 65-70 kDa and showed the highest proteolytic activity at a 1:4 ratio of ethanol precipitation (p < 0.05). The optimal activity of the measured enzyme fraction was determined to be at pH 9.0 and 50 °C, and the proteolytic activity of ESF was almost inhibited by phenyl methyl sulphonyl fluoride (PMSF, 2 mM), a serine protease inhibitor. Compared to Alcalase and papain, extensively used as commercial enzymes, the silkworm thorn fruit powder was less effective in hydrolyzing SPI and WPC. Nevertheless, SPI and WPC hydrolyzates mediated with silkworm thorn fruit powder showed even better antioxidant activities than those mediated with Alcalase and papain. Thus, our results show the potential application of silkworm thorn fruit as a novel source of plant protease for producing human-grade protein hydrolyzates.

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.

Peptidases from Maclura Pomifera for Preparation of Food Protein Hydrolysates: Purification by Single-Step Chromatography and Characterization of Pomiferin I

Our objective was to isolate peptidases from the latex of Maclura pomifera fruits and use them to hydrolyze food proteins, as well as to purify and characterize the main peptidase. Two partially purified proteolytic extracts were prepared by ethanol (EE) and acetone (AE) precipitation from an aqueous suspension of exuded fruit latex. EE was used to hydrolyze food proteins with a ratio of 0.19 caseinolytic units (Ucas) per mg of substrate. Different values of hydrolysis degree were observed for hydrolysates of egg white, soy protein isolate, and casein at 180 min (9.3%, 31.1%, and 29.1%, respectively). AE was employed to purify a peptidase which exhibited an isoelectric point (pI) of 8.70 and whose abundance in AE was 28.3%. This enzyme was purified to homogeneity using a single-step procedure by cation-exchange chromatography, achieving an 8.1-fold purification and a yield of 16.7%. The peptidase was named pomiferin I and showed a molecular mass of 63,177.77 Da. Kinetic constants (K_M 0.84 mM, V_max 27.50 uM s^-1, k_cat 72.37 s^-1, and k_cat/K_M 86.15 mM^-1 s^-1) were determined employing N-α-carbobenzoxy-L-alanyl-p-nitrophenyl ester as substrate. Analysis by PMF showed only partial homology of pomiferin I with a serine peptidase from a species of the same family.

A contradictory action of procoagulant ficin by a fibrinolytic serine protease from Egyptian Ficus carica latex

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We purified a serine protease from Ficus carica latex.

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Serine protease had a high tendency to hydrolyze fibrinogin.

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Serine protease inhibited blood coagulation.

Ficus carica is one of the most popular and edible plants. Its trees emanate latex of high medical importance. The well-studied procoagulant effect of ficin is a hallmark of this latex which protrudes an interesting question of how can the plant control this effect? In the present work, we purified and characterized a serine protease (FPIII) with fibrinolytic activity from F. carica latex and study the anticoagulant character of the latex. FPIII was inhibited by PMSF and its molecular weight was 48 kDa. The optimum pH and temperature of FPIII were detected at 8.5 and 60 °C, respectively. The activation energy of FPIII was 7 kcal/mol and was thermal stable up to 60 °C. FPIII tended to hydrolyze different protein substrates and showed a good catalytic efficiency (K_cat/K_m). The anticoagulant effects and fibrinogenolytic activities of latex crude extract and FPIII were detected, which controls the procoagulant effect of ficin.

Encapsulation of β-amylase in water-oil-water enzyme emulsion liquid membrane (EELM) bioreactor for enzymatic conversion of starch to maltose

The β-amylase was encapsulated in emulsion liquid membrane (ELM), which acted as a reactor for conversion of starch to maltose. The membrane phase was consisted of surfactant (span 80), stabilizer (polystyrene), carrier for maltose transport (methyl cholate) and solvent (xylene). The substrate starch in feed phase entered into the internal phase by the process of diffusion and hydrolyzed to maltose by encapsulated β-amylase. Methyl cholate present in the membrane acts as a carrier for the product maltose, which helps in transport of maltose to feed phase from internal aqueous phase. The residual activity of β-amylase after the five-reaction cycle was found to decrease to ∼70%, which indicated possibility to recycle the components of the emulsion and enzyme. The pH and temperature of the encapsulated enzyme were found to be optimum at 5.5 and 60 °C, respectively. The novelty of the present work lies in the development of Enzyme Emulsion Liquid Membranes (EELM) bioreactor for the hydrolysis of starch into maltose mediated by encapsulated β-amylase. The attempt has been made for the first time for the successful encapsulation of β-amylase into EELM. The best results gave the highest residual enzyme activity (94.1%) and maltose production (29.13 mg/mL).

Anthelminthic potential of the Ficus insipida latex on monogeneans of Colossoma macropomum (Serrasalmidae), a medicinal plant from the Amazon

INTRODUCTION

Herbal therapy is a potentially beneficial alternative for fish aquaculture, since it may be cheaper and more effective than chemotherapy. The aim of this study was to investigate the in vitro efficacy of Ficus insipida latex on monogeneans of Colossoma macropomum gills.

MATERIALS AND METHODS

To evaluate the anthelmintic activity, four concentrations of F. insipida latex (250, 500, 750 and 1000 µL/L) and exposure time to cause immobilization on monogeneans were used. In addition, two control groups, being one with water from the breeding tank and the other with breeding water from the tank + 70% ethyl alcohol were used.

RESULTS

At the concentration of 250 µL/L of F. insipida latex, the immobilization of the monogeneans occurred after 4 h of exposure, while at the concentration of 500 µL/L, it occurred after 2 h. At the concentrations of 750 and 1000 µL/L of F. insipida latex, the immobilization of the monogeneans occurred after 1 h and 30 min, respectively. After exposure to 250 µL/L of F. insipida latex, 100% of immobilization of monogeneans was observed within 4 h, to 500 and 750 µL/L, 100% immobilization occurred within 4 h and to 1000 µL/L, 100% mortality occurred after 2 h.

CONCLUSIONS

Thus, we recommended the use of 1000 μL/L of F. insipida latex for therapeutic baths in of C. macropomum against monogeneans, after previous test of toxicity.

Antifungal Proteins from Plant Latex

Latex, a milky fluid found in several plants, is widely used for many purposes, and its proteins have been investigated by researchers. Many studies have shown that latex produced by some plant species is a natural source of biologically active compounds, and many of the hydrolytic enzymes are related to health benefits. Research on the characterization and industrial and pharmaceutical utility of latex has progressed in recent years. Latex proteins are associated with plants' defense mechanisms, against attacks by fungi. In this respect, there are several biotechnological applications of antifungal proteins. Some findings reveal that antifungal proteins inhibit fungi by interrupting the synthesis of fungal cell walls or rupturing the membrane. Moreover, both phytopathogenic and clinical fungal strains are susceptible to latex proteins. The present review describes some important features of proteins isolated from plant latex which presented in vitro antifungal activities: protein classification, function, molecular weight, isoelectric point, as well as the fungal species that are inhibited by them. We also discuss their mechanisms of action.

A novel serine protease from pseuderanthemum latifolium B. Hansen: Characterization and fibrino(geno)lytic activities

Protease (PPL) was isolated from Pseuderanthemum latifolium B. Hansen and had a molecular mass of 70 kDa. The N-terminal sequence of PPL showed 70-80% similarity with of subtilisin-like serine proteases from plants, but it did not show any sequence homology with known plant proteases. Serine protease inhibitors (PMSF, DFP) effectively blocked about 90% of PPL activity. PPL was highly activity at the pH range from 6 to 9 and temperatures from 50 °C to 80 °C, with an optimum at pH 7.0 and temperatures 70 °C. PPL had stability in a variety of pH, temperature, surfactant and oxidizing agents. PPL with concentration of 2.5 µg completely hydrolyzed the Aα-chain of fibrinogen within 5 min and hydrolyzed the Bβ and the γ-chain after 10 h. Fibrin also was strong hydrolyzed by PPL with concentration of 0.3 µg. Thus, PPL is a unique serine protease, which it had strong fibrino(geno)lytic activities.

Three phase partitioning to concentrate milk clotting proteases from Wrightia tinctoria R. Br and its characterization

Wrightia tinctoria stem proteases were partially purified for the first time through a non-chromatographic technique, three phase partitioning (TPP), to concentrate the milk clotting proteases. Various parameters like salt and solvent concentration that affect the partitioning of the protease were examined. Maximum recovery and purification fold of the protease activity were found in the interfacial phase (IP) with 60% ammonium sulphate and 1:1 crude enzyme to t-butanol. Optimum pH and temperature of the enzyme fraction were found to be 7.5 and 50 °C respectively. Inhibition studies revealed its serine nature. Non-denaturing PAGE, Zymography and 2D PAGE of IP revealed presence of three different caseinolytic proteases of molecular weights 95.62 kDa, 91.11 kDa and 83.23 kDa with pI 3.89, 5.45 and 5.43 respectively. Both aqueous and lyophilized form of IP were remarkably stable retaining complete activity at 4 °C for 3 weeks. Electrophoretic analysis of casein hydrolysate by IP at different incubation time indicated a time dependent substrate subunit specificity with hydrolysis of κ-casein commencing after 10 min followed by α and β caseins. This pattern was found similar to that by commercial vegetable coagulant, Enzeco®. Study details the effectiveness of TPP concentrated W. tinctoria proteases as a vegetable coagulant alternative in cheese making.

Rheological and structural properties of enzyme-induced gelation of milk proteins by ficin and Polyporus badius

The rheological and microstructural characteristics of ewes’ milk curd obtained by coagulating with milk‐clotting enzymes, including ficin extract and Polyporus badius were evaluated. The gelation of milk was examined by small amplitude oscillatory shear measurements (SAOS). Different concentrations of ficin and P. badius extracts (1, 3, and 5%) were utilized to coagulate milk proteins. The ewes’ samples containing ficin and mushroom enzymes were heated from 25 to 45°C at a heating rate 1°C/min and kept for 30 min. Then, the curds were cooled down to 25°C with the same heating rate. The ficin extract could induce stronger gels at 45°C and 5% ficin. Similar results were also found for 5% P. badius extract and incubation at 45°C. However, P.badius gels achieved a network with more viscous characteristics and had a softer texture than ficin gels. Therefore, it may be concluded the induced gels with mushroom had higher moisture and lower protein contents, which related to the high proteolytic activity of P. badius. The microstructure survey showed that the mushroom‐induced gel had a more compact structure. By increasing enzyme concentration, both gels showed a coarser and more compact protein network. Whereas, the P. badius gels had more fusions and folds which indicate the greater proteolysis occurred during gelation and there was greater breakdown of protein. Our findings suggest the application of ficin and P. badius enzymes to develop a novel procedure to coagulate milk proteins and providing new structures in food systems.

A critical review on serine protease: Key immune manipulator and pathology mediator

Proteolytic activity is fundamental to survival, so it is not surprising that all living organisms have proteases, especially seine protease. This enzyme in its numerous isoforms and homologues, constitutes the quintessential offence and defence factors, in the form of surface proteins, secreted molecules, gut digestive enzymes, venom in specialised glands or plant latex, among other manifestations. Occurring as trypsin, chymotrypsin, elastase, collagenase, thrombin, subtilisin etc., it mediates a diverse array of functions, including pathological roles as inflammatory, coagulatory to haemorrhagic. This review emphasizes that despite the superficial differences in mechanisms, most health issues, be they infectious, allergic, metabolic, or neural have a common conduit. This enzyme, in its various glycosylated forms leads to signal misinterpretations, wreaking havoc. However, organisms are endowed with serine protease inhibitors which might restrain this ubiquitous yet deleterious enzyme. Hence, serine proteases-driven pathogenesis and antagonising role of inhibitors is the focal point of this critical review.

Purification and characterization of a novel trypsin-like protease from green-seeded chickpea (Cicer arientum)

The present study describes the purification and physicochemical and biochemical characterization of trypsin-like protease from green-seeded chickpea (Cicer arientum). The crude extract of chickpea trypsin (CpT) was obtained by homogenization followed by differential ammonium sulfate precipitation. The CpT was purified by ion-exchange chromatography on diethylaminoethyl (DEAE) column, pre-equilibrated with 20 mM tris-CaCl₂ buffer (pH 8.2) with a flow rate of 0.5 mL min^-1. The molecular weight and purity of ∼23 kDa of CpT were determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Activity of protease was determined using Nα-benzoyl-DL-arginine-p-nitroanilide as chromogenic substrate and CpT purified showed a specific inhibitor activity of 26978.7697 U mg^-1, fold purity of 9.8, and the yield of 70.2%. The characterization was performed for thermal stability, pH profile, and effect of various inhibitors on enzymatic activity. The protein isolated showed stability in the neutral to mild alkaline pH range and thermostability up to 50°C. CpT confirmed its serine nature as it was appreciably inhibited by serine protease inhibitors (maximum 6%), whereas metalloprotease inhibitors barely affected the activity of the enzyme (85%). To the best of our knowledge, it is first reported on purification of protease with trypsin-like properties, from this source.

Three phase partitioning, a scalable method for the purification and recovery of cucumisin, a milk-clotting enzyme, from the juice of Cucumis melo var. reticulatus

Cucumisin [EC 3.4.21.25] was first purified from Cucumis melo var. reticulatus juice by three-phase partitioning (TPP). Optimum purification parameters of the TPP system were determined as 60% ammonium sulfate saturation with 1.0:1.25 ratio of crude extract: t-butanol at pH and temperature of 8.0 and 20°C, respectively. Cucumisin was purified with 4.61 purification fold and 156% activity recovery. The molecular weight of the recovered cucumisin was determined as 68.4kDa and its isoelectric point is 8.7. Optimum pH and temperature of cucumisin were pH 9.0 and 60-70°C, respectively. The protease was very stable at 20-70°C and a pH range of 2.0-12.0. Km and Vmax constants were 2.24±0.22mgmL^-1 and 1048±25μ Mmin^-1, respectively. The enzyme was stable against numerous metal ions and its activity was highly enhanced by Ca²⁺, Mg²⁺, and Mn⁺². Cucumisin activity was 2.35-folds increased in the presence of 5mM of CaCl₂. It was inactivated by Co²⁺, Cd²⁺, Zn²⁺ and Fe²⁺ and dramatically by PMSF. Cucumisin milk-clotting activity was highly stable when stored under freezing (-20°C) compared at 4°C and 25°C. Finally, TPP revealed to be a useful strategy to concentrate and purify cucumisin for its use as a milk-clotting enzyme for cheese-making.

Characterization of the binding of a glycosylated serine protease from Euphorbia cf. lactea latex to human fibrinogen

In this study, the binding of a glycosylated serine protease (EuP-82) with human fibrinogen was investigated by isothermal titration calorimetry (ITC). ITC analysis indicated that the binding of EuP-82 to fibrinogen in the conditions with or without the activator (Ca²⁺ ) was an exothermic reaction (dominant negative enthalpy), which tended to be driven by hydrogen bonding and van der Waals interactions. In contrast, the binding of fibrinogen-EuP-82 in the condition with the inhibitor (Zn²⁺ ) was an unfavorable endothermic reaction. EuP-82 could not inhibit the platelet activity in citrated whole blood via the ADP-receptor pathways (mainly, P2Y1 and P2Y12), but it could enhance the platelet aggregation. The ITC together with whole blood platelet aggregation suggested that EuP-82 provided multiple fibrinogen-binding sites that were not related to the arginine-glycine-aspartate (RGD) and the dodecapeptide sequences of fibrinogen. In addition, EuP-82 had neither thrombin-like activity nor anticoagulant activity. The SR-FTIR spectra revealed that EuP-82 was a glycoprotein. Deglycosylation of EuP-82 did not affect its proteolytic activity. Moreover, EuP-82 did not exhibit any toxicity to the living cells (NIH-3T3). This study supports that EuP-82 may be useful for wound-healing material through stabilizing the clot via the platelet induction for the first process.

Microencapsulation of purified amylase enzyme from pitaya (Hylocereus polyrhizus) peel in Arabic gum-chitosan using freeze drying

Amylase is one of the most important enzymes in the world due to its wide application in various industries and biotechnological processes. In this study, amylase enzyme from Hylocereus polyrhizus was encapsulated for the first time in an Arabic gum-chitosan matrix using freeze drying. The encapsulated amylase retained complete biocatalytic activity and exhibited a shift in the optimum temperature and considerable increase in the pH and temperature stabilities compared to the free enzyme. Encapsulation of the enzyme protected the activity in the presence of ionic and non-ionic surfactants and oxidizing agents (H₂O₂) and enhanced the shelf life. The storage stability of amylase is found to markedly increase after immobilization and the freeze dried amylase exhibited maximum encapsulation efficiency value (96.2%) after the encapsulation process. Therefore, the present study demonstrated that the encapsulation of the enzyme in a coating agent using freeze drying is an efficient method to keep the enzyme active and stable until required in industry.

A new serine protease from the leaves of Thespesia populnea

A serine protease was purified 6.9-fold from the leaves of Thespesia populnea using ammonium sulfate fractionation followed by CM-cellulose and Sephadex G-100 chromatography. The purified enzyme was named populnein and was characterized. It was made up of a single polypeptide, and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) analysis showed that the enzyme had a molecular mass of 14,518 Da. Inhibition of enzyme activity by phenyl methane sulfonyl fluoride indicates that populnein belongs to the class of serine proteases. The enzyme had appreciable pH and temperature stability. The activity of the enzyme was optimal at pH 8.0 and temperature 40°C. The enzyme was thermostable and retained 85% of its activity at 70°C after 1 hr. The enzyme was also resistant to autodigestion. The stabilization of the membrane of red blood cells exhibited by the protease populnein was found to be higher than for diclofenac. More studies are necessary to investigate the biological activity and applications of serine protease of T. populnea.

A novel serine protease with human fibrino(geno)lytic activities from Artocarpus heterophyllus latex

A protease was isolated and purified from Artocarpus heterophyllus (jackfruit) latex and designated as a 48-kDa antimicrobial protease (AMP48) in a previous publication. In this work, the enzyme was characterized for more biochemical and medicinal properties. Enzyme activity of AMP48 was strongly inhibited by phenylmethanesulfonyl fluoride and soybean trypsin inhibitor, indicating that the enzyme was a plant serine protease. The N-terminal amino acid sequences (A-Q-E-G-G-K-D-D-D-G-G) of AMP48 had no sequence similarity matches with any sequence databases of BLAST search and other plant serine protease. The secondary structure of this enzyme was composed of high α-helix (51%) and low β-sheet (9%). AMP48 had fibrinogenolytic activity with maximal activity between 55 and 60°C at pH 8. The enzyme efficiently hydrolyzed α followed by partially hydrolyzed β and γ subunits of human fibrinogen. In addition, the fibrinolytic activity was observed through the degradation products by SDS-PAGE and emphasized its activity by monitoring the alteration of secondary structure of fibrin clot after enzyme digestion using ATR-FTIR spectroscopy. This study presented the potential role to use AMP48 as antithrombotic for treatment thromboembolic disorders such as strokes, pulmonary emboli and deep vein thrombosis.

Subtilases - versatile tools for protein turnover, plant development, and interactions with the environment

Subtilases (SBTs) constitute a large family of serine peptidases. They are commonly found in Archaea, Bacteria and Eukarya, with many more SBTs in plants as compared to other organisms. The expansion of the SBT family in plants was accompanied by functional diversification, and novel, plant-specific physiological roles were acquired in the course of evolution. In addition to their contribution to general protein turnover, plant SBTs are involved in the development of seeds and fruits, the manipulation of the cell wall, the processing of peptide growth factors, epidermal development and pattern formation, plant responses to their biotic and abiotic environment, and in programmed cell death. Plant SBTs share many properties with their bacterial and mammalian homologs, but the adoption of specific roles in plant physiology is also reflected in the acquisition of unique biochemical and structural features that distinguish SBTs in plants from those in other organisms. In this article we provide an overview of the earlier literature on the discovery of the first SBTs in plants, and highlight recent findings with respect to their physiological relevance, structure and function.

Selective and reversible thiol-pegylation, an effective approach for purification and characterization of five fully active ficin (iso)forms from Ficus carica latex

The latex of Ficus carica constitutes an important source of many proteolytic components known under the general term of ficin (EC 3.4.22.3) which belongs to the cysteine proteases of the papain family. So far, no data on the purification and characterization of individual forms of these proteases are available. An effective strategy was used to fractionate and purify to homogeneity five ficin forms, designated A, B, C, D1 and D2 according to their sequence of elution from a cation-exchange chromatographic support. Following rapid fractionation on a SP-Sepharose Fast Flow column, the different ficin forms were chemically modified by a specific and reversible monomethoxypolyethylene glycol (mPEG) reagent. In comparison with their un-derivatized counterparts, the mPEG-protein derivatives behaved differently on the ion-exchanger, allowing us for the first time to obtain five highly purified ficin molecular species titrating 1mol of thiol group per mole of enzyme. The purified ficins were characterized by de novo peptide sequencing and peptide mass fingerprinting analyzes, using mass spectrometry. Circular dichroism measurements indicated that all five ficins were highly structured, both in term of secondary and tertiary structure. Furthermore, analysis of far-UV CD spectra allowed calculation of their secondary structural content. Both these data and the molecular masses determined by MS reinforce the view that the enzymes belong to the family of papain-like proteases. The five ficin forms also displayed different specific amidase activities against small synthetic substrates like dl-BAPNA and Boc-Ala-Ala-Gly-pNA, suggesting some differences in their active site organization. Enzymatic activity of the five ficin forms was completely inhibited by specific cysteine and cysteine/serine proteases inhibitors but was unaffected by specific serine, aspartic and metallo proteases inhibitors.

Decolorization of crude latex by activated charcoal, purification and physico-chemical characterization of religiosin, a milk-clotting serine protease from the latex of Ficus religiosa

The crude latex of Ficus religiosa is decolorized by activated charcoal. Decolorization follows the Freundlich and Langmuir equations. A serine protease, named religiosin, has been purified to homogeneity from the decolorized latex using anion exchange chromatography. Religiosin is a glycoprotein with a molecular mass of 43.4 kDa by MALDI-TOF. Religiosin is an acidic protein with a pI value of 3.8 and acts optimally at pH 8.0-8.5 and temperature 50 degrees C. The proteolytic activity of religiosin is strongly inhibited by PMSF and chymostatin indicating that the enzyme is a serine protease. The extinction coefficient (epsilon(1%)(280)) of religiosin is 29.47 M(-1) cm(-1)with 16 tryptophan, 26 tyrosine, and 11 cysteine residues per molecule. The enzyme shows broad substrate specificity against natural as well as synthetic substrates with an apparent K(m) of 0.066 mM and 6.25 mM using casein and Leu-pNA, respectively. MS/MS analysis confirms the novelty of the enzyme. Religiosin is highly stable against denaturants, metal ions, and detergents as well as over a wide range of pH and temperature. In addition, the enzyme exhibits milk-clotting as well as detergent activity.