• Parasites, Hosts and Diseases
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• v.42 no.2
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• pp.61-66
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• 2004

The plasmepsins are the aspartic proteases of malaria parasites. Treatment of aspartic protease inhibitor inhibits hemoglobin hydrolysis and blocks the parasite development in vitro suggesting that these proteases might be exploited their potentials as antimalarial drug targets. In this study, we determined the genetic variations of the aspartic proteases of Plasmodium vivax (PvPMs) of wild isolates. Two plasmepsins (PvPM4 and PvPM5) were cloned and sequenced from 20 P. vivax Korean isolates and two imported isolates. The sequences of the enzymes were highly conserved except a small number of amino acid substitutions did not modify key residues for the function or the structure of the enzymes. The high sequence conservations between the plasmepsins from the isolates support the notion that the enzymes could be reliable targets for new antimalarial chemotherapeutics.

• Parasites, Hosts and Diseases
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• v.53 no.1
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• pp.1-11
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• 2015

Serine proteases form one of the most important families of enzymes and perform significant functions in a broad range of biological processes, such as intra- and extracellular protein metabolism, digestion, blood coagulation, regulation of development, and fertilization. A number of serine proteases have been identified in parasitic helminths that have putative roles in parasite development and nutrition, host tissues and cell invasion, anticoagulation, and immune evasion. In this review, we described the serine proteases that have been identified in parasitic helminths, including nematodes (Trichinella spiralis, T. pseudospiralis, Trichuris muris, Anisakis simplex, Ascaris suum, Onchocerca volvulus, O. lienalis, Brugia malayi, Ancylostoma caninum, and Steinernema carpocapsae), cestodes (Spirometra mansoni, Echinococcus granulosus, and Schistocephalus solidus), and trematodes (Fasciola hepatica, F. gigantica, and Schistosoma mansoni). Moreover, the possible biological functions of these serine proteases in the endogenous biological phenomena of these parasites and in the host-parasite interaction were also discussed.

• The Plant Pathology Journal
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• v.28 no.2
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• pp.197-201
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• 2012

Potyviruses express their RNA genomes through the production of polyproteins that are processed in host cells by three virus-encoded proteases. Soybean plants produce large amounts of protease inhibitors during seed development and in response to wounding that could affect the activities of these proteases. The in vitro activities of two of the proteases of Soybean mosaic virus (SMV) and Tobacco vein mottling virus (TVMV) were compared in the rabbit reticulocyte lysate in vitro translation system using synthetic RNA transcripts. Transcripts produced from SMV and TVMV cDNAs that included the P1 and helper component-protease (HC-Pro) coding regions directed synthesis of protein products that were only partially processed. Unprocessed poly-proteins were not detected from transcripts that included all of the P1, HC-Pro, P3 and portions of the cylindrical inclusion protein coding regions of either virus. Addition of soybean trypsin inhibitor to in vitro translation reactions increased the accumulation of the unprocessed polyprotein from TVMV transcripts, but did not alter the patterns of proteins produced from SMV. These experiments suggest that SMV-and TVMV-encoded proteases are differentially sensitive to protease inhibitors.

• International Journal of Oral Biology
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• v.44 no.2
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• pp.37-42
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• 2019

Oral squamous cell carcinoma (OSCC) is the most common oral malignancy and an increasing global public health problem. OSCC frequently invades the jaw bone. OSCC-induced bone invasion has a significant impact on tumor stage, treatment selection, patient outcome, and quality of life. A number of studies have shown that osteoclast-mediated bone resorption is a major step in the progression of bone invasion by OSCC; however, the molecular mechanisms involved in OSCC bone invasion are not yet clear. In this review, we present the clinical types of OSCC bone invasion and summarize the role of key molecules, including proteases, cytokines, and growth factors, in the sequential process of bone invasion. A better understanding of bone invasion will facilitate the discovery of molecular targets for early detection and treatment of OSCC bone invasion.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.8
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• pp.1353-1358
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• 2004

This study was conducted to increase crude protein and reducing sugar contents in pollen extracts by proteases. Four commercial neutral proteases (Alcalase 2.4L, Protamex, Flavozyme and Protease A) and two alkaline proteases (Protease S and Protease P) were used to prepare acorn and Darae pollen extracts. Contents of moisture, ash, crude protein and crude fat of acorn pollen were 5.2%, 2.7%, 6.2% and 22.3%, respectively, while those of Darae pollen were 5.4%, 2.8%, 1.8% and 27.8%, respectively. Contents of crude protein and reducing sugar in pollen extracts were increased by proteases. Alcalase 2.4L was the most effective in increasing protein contents while Protease A in increasing reducing sugar contents. It is suggested the use of proteases is one of the potential methods for increasing the contents of crude protein and reducing sugar in preparation of pollen extracts.

• Food Engineering Progress
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• v.15 no.1
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• pp.41-47
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• 2011

The defatted rice bran (DRB) was enzymatically hydrolyzed using eight commercial proteases for 4hr at optimum pH and temperature. Proteolytic hydrolysates were examined in supernatant and precipitate using lowry, semimicro kjeldahl and gravimetric method using weight difference before and after enzymatic hydrolysis. In lowry and kjeldahl protein assay method, two proteases (Alcalase and Protease N) were found to be the most effective enzymes. In gravimetric method, 60.6~118.3 mg protein/g DRB was hydrolyzed after eight commercial proteases treatments. Similar to lowry and kjeldahl method, 118.3 and 107.1 mg protein/g DRB were hydrolyzed after Alcalase and Protease N treatments, respectively. When two or three effective proteases (Protamex, Alcalase and Protease N) were applied at one time to obtain synergistic effect, significant increase (P<0.05) was observed when three proteases were applied at one time (63.4 mg protein/g DRB in lowry method and 204.5 mg protein/g DRB in gravimetric method). This result suggests that Alcalase and Protease N were the most effective enzymes for proteolysis of DRB and three commercial enzymes (Protamex, Alcalase and Protease N) showed the synergistic effect on the hydrolysis of DRB.

• BMB Reports
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• v.40 no.4
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• pp.604-609
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• 2007

An Asp/His catalytic site of 10-formyltetrahydrofolate dehydrogenase (FDH) was suggested to have a similar catalytic topology with the Asp/His catalytic site of serine proteases. Many studies supported the hypothesis that serine protease inhibitors can bind and modulate the activity of serine proteases by binding to the catalytic site of serine proteases. To explore the possibility that soybean trypsin inhibitor (SBTI) can recognize catalytic sites of FDH and can make a stable complex, we carried out an SBTI-affinity column by using rat liver homogenate. Surprisingly, the Rat FDH molecule with two typical liver proteins, carbamoyl-phosphate synthetase 1 (CPS1) and betaine homocysteine S-methyltransferase (BHMT) were co-purified to homogeneity on SBTI-coupled Sepharose and Sephacryl S-200 followed by Superdex 200 FPLC columns. These three liver-specific proteins make a protein complex with 300 kDa molecular mass on the gel-filtration column chromatography in vitro. Immuno-precipitation experiments by using anti-FDH and anti-SBTI antibodies also supported the fact that FDH binds to SBTI in vitro and in vivo. These results demonstrate that the catalytic site of rat FDH has a similar structure with those of serine proteases. Also, the SBTI-affinity column will be useful for the purification of rat liver proteins such as FDH, CPS1 and BHMT.

• Journal of Microbiology and Biotechnology
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• v.10 no.5
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• pp.667-667
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• 2000

Pseudomonas sp. BK7, an alkalophile, displayed the highest growth and protease activity when grown in a fermenter which was controlled at a pH level of 9.0, and the enzyme production was significantly enganced by the increase of agitation speed. Two formas of alkaline proteases (BK7-1 and BK7-2) were fractionated and purified to near homogeneity. Protease BK7-1 was purified through CM-Sepharose CL-6B and Sephadex G-75 column chromatographies, and Protease BK7-2 was purified through CM-Sepharose CL-6B and Sephadex G-75 column chromatographies, and Protease BK7-2 was purified through CM-Sepharose CL-6B, DEAE-Sepharose, and Sephadex G-75 column chromatographies. The molecular weights of proteases BK7-1 and BK7-2 determined by gel filtration chromatography were 20,700 and 40,800, respectively. The $K_m$ value, isoelectric point, and optimum pH of protease BK7-1 were 2.55 mg/ml, 11.0 and 11.0, respectively, whereas those of protease BK7-2 were 1.57 mg/ml, 7.2, and 10.0, respectively. Both protease were practically stable in the pH range of 5-11. The optimum temperatures for the activities of both protease BK7-1 and BK7-2 were 50℃ and 45℃, respectively. About 56% of the original protease BK7-2 activity remained after being treated at 50℃ for 30 min but protease BK7-1 was rapidly inactivated at above 25℃. Both proteases were completely inhibited by phenylmethane sulfonyl fluoride, a serine protease inhibitor. Protease BK7-2 was stable against EDTA, EGTA, STP, and detergents such as SDS and LAS, whereas protease BK7-1 was found to be unstable.

• Journal of Microbiology and Biotechnology
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• v.23 no.8
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• pp.1133-1139
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• 2013

Enzymatic decomposition of gelatin layers on used X-ray films and repeated utilization of the enzyme for potential application in silver recovery were investigated using keratinolytic serine proteases from Purpureocillium lilacinum LPS # 876. At pH 9.0, the enzymatic reaction was enhanced by the increase of enzyme concentration or by the increase of the temperature up to $60^{\circ}C$. Under the conditions of 6.9 U/ml, $60^{\circ}C$, and pH 9.0, hydrolysis of the gelatin layers and the resulting release of silver particles were achieved within 6 min. The protective effect of polyols against thermal denaturation was investigated. The presence of glycerol and propylene glycol increased enzyme stability. When the reusability of the enzyme for gelatin hydrolysis was tested, it could be seen that it could be effectively reused for more cycles when glycerol was added, compared with the enzyme without protective agents. The results of these repeated treatments suggested that a continuous process of recycling silver from used X-ray is feasible. Keeping in mind that recycling is (at the present time) needed and imperative, it can be remarked that, in this research, three wastes were successfully used: hair waste in order to produce serine proteases; glycerol in order to enhance enzyme thermal stability; and used X-ray films in order to recover silver and PET films.

• The Korean Journal of Mycology
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• v.36 no.2
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• pp.178-182
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• 2008

Although the number of patients with Acanthamoeba keratitis has increased dramatically since the widespread use of contact lens, it is still very hard to cure the disease. The proteases from the Acanthamoeba were reported to play important role in the pathogenesis of keratitis. In this study, the inhibitors for extracellular serine proteases of A. castellanii were screened from the extracts of 230 mushroom samples collected from various regions of Korea. The mushrooms were extracted with methanol and water ($65^{\circ}C$). Filtered and concentrated extracts (0.3 mg/ml) were preincubated with proteases before addition of peptide substrate N-succinyl-ala-ala-pro-phe p-anilide. The selected extracts showing strong inhibitory effects were characterized. Although inhibition with single extract was not so high enough, the complete inhibition was achieved with combination of two extracts. The selected extract showed little effect on other serine proteases such as thrombin (human and bovine) and on general protease such as protease K.