• Journal of Animal Science and Technology
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• v.51 no.6
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• pp.527-536
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• 2009

A potent protein degrading bacterium was isolated from soil samples of different environments. Polyphasic taxonomic studies and phylogenetic 16S rRNA sequence analyses led to identify the isolate IB No. 11 as a strain of Bacillus subtilis. The isolated strain was recognized to produce protease constitutively, and the maximum production (1.64 units/ml) was attained in a shake flask culture when the isolate was grown at $40^{\circ}C$, for 32 h in basal medium supplemented with starch (0.25%) and gelatin (1.25%) as sole carbon and nitrogen source, respectively. The optimum pH and temperature for the protease activity were determined to be pH 7.0 and $50^{\circ}C$, respectively. $Ca^{2+}$ and $Mn^{2+}$ enhanced remarkably the protease activity but neither showed positive effect on the protease's thermal stability. In addition, it was observed that the protease was fairly stable in the pH range of 6.5-8.0 and at temperatures below $50^{\circ}C$, and it could be a good candidate for an animal feed additive. The inhibition profile of the protease by various inhibitors indicated that the enzyme is a member of serine-proteases. A combination of UV irradiation and NTG mutagenesis allowed to develop a protease hyper-producing mutant strain coded as IB No. 11-4. This mutant strain produced approximately 3.23-fold higher protease activity (6.74 units/mg) than the parent strain IB No. 11 when grown at $40^{\circ}C$ for 32h in the production medium. The protease production profile of the selected mutants was also confirmed by the zymography analysis.

• Journal of Applied Biological Chemistry
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• v.49 no.4
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• pp.135-139
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• 2006

A alkalophilic strain, Bacillus licheniformis MH31 producing an alkaline protease was isolated from mine soil of Boryeong in Korea. Production of a high level of alkaline protease was achieved 42 h after incubation when the bacterium was grown at pH 9.0 and $35^{\circ}C$ in Horikoshi medium supplemented with 0.5%(w/v) starch and 1%(w/v) skim milk as carbon and nitrogen source, respectively. The molecular weight of partially purified enzyme was estimated to be 30 kDa by SDS-PAGE and its optimum pH was pH 10. The enzyme showed optimum temperature at $50^{\circ}C$, and was stable up to $60^{\circ}C$ after 1 h incubation. The protease was strongly inhibited by 1 mM of PMSF which was known well as strong inhibitor of serine proteases, but almost not inhibited by 5 mM of EDTA and 1,10-phenanthroline. When the protein hydrolysis products of 1% skim milk by partially purified protease was compared with available commercial proteases using HPLC analysis, most of hydrolysis products were detected below molecular weight of 10,000 and the hydrolysis ratio of purified enzyme was 24.8% lower than those(above 32%) of commercial proteases.

• Journal of Microbiology
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• v.40 no.1
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• pp.26-32
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• 2002

From the culture supernatant of the psychrotrophic strain of Bacillus amyloliquefaciens an extracellular serine protease was purified to apparent homogeneity by successive purification steps using QAE-Sephadex, SP-Sephadex and Sephacryl S-100 column chromatography. The pretense is monomeric, with a relative molecular mass of 23,000. It is inhibited by the serine protease inhibitor phenylmethylsulfonyl fluoride, but not by EDTA. The enzyme is most active at pH 9-10 and at $45^{\circ}C$, although it is unstable at $60^{\circ}C$.

• Journal of Microbiology and Biotechnology
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• v.33 no.2
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• pp.195-202
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• 2023

Protease is a widely used enzyme particularly in the detergent industry. In this research, we aimed to isolate alkaline protease-producing bacteria for characterization as a laundry detergent additive. The screening of alkaline protease production was investigated on basal medium agar plus 1% skim milk at pH 11, with incubation at 30℃. The highest alkaline protease-producing bacterium was 6BS15-4 strain, identified as Bacillus gibsonii by 16S rRNA gene sequencing. While the optimum pH was 12.0, the strain was stable at pH range 7.0-12.0 when incubated at 45℃ for 60 min. The alkaline protease produced by B. gibsonii 6BS15-4 using dairy effluent was characterized. The optimum temperature was 60℃ and the enzyme was stable at 55℃ when incubated at pH 11.0 for 60 min. Metal ions K⁺, Mg²⁺, Cu²⁺, Na⁺, and Zn²⁺ exhibited a slightly stimulatory effect on enzyme activity. The enzyme retained over 80% of its activity in the presence of Ca²⁺, Ba²⁺, and Mn²⁺. Thiol reagent and ethylenediaminetetraacetic acid did not inhibit the enzyme activity, whereas phenylmethylsulfonyl fluoride significantly inhibited the protease activity. The alkaline protease from B. gibsonii 6BS15-4 demonstrated efficiency in blood stain removal and could therefore be used as a detergent additive, with potential for various other industrial applications.

• The Korea Journal of Herbology
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• v.22 no.4
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• pp.21-28
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• 2007

Objectives : Kyenegum has been popularly used long as the digestive. The purpose of this study was to investigate the purification and characteristics of protease obtained from Kyenegum crude enzyme. Methods : Kyenegum protease was purified by precipitation with ammonium sulfate followed by SP-Spharose ion exchange chromatography. The molecular weight of Kyenegum protease was estimated by SDS-PAGE electrophoresis. Results : Kyenegum protease was 3,087 units/mg protein specific activity, 14.5 purification fold and 9.8 % recovery. The molecular weight of protease was estimated to be 18 kDa. The isoelectric point was pI 8.97 and values of Km and Vmax of its were 48 mg/mL and 2 units/min, respectively. Conclusion : The result suggests that the protease obtained from Kyenegum has excellent stability of temperature, acid and collagen substrate specificity.

• Journal of Microbiology and Biotechnology
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• v.28 no.3
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• pp.448-453
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• 2018

In this study, a 107 kDa protease from psychrophilic Janthinobacterium lividum PAMC 26541 was purified by anion-exchange chromatography. The specific activity of the purified protease was 264 U/mg, and the overall yield was 12.5%. The J. lividum PAMC 25641 protease showed optimal activity at pH 7.0-7.5 and $40^{\circ}C$. Protease activity was inhibited by PMSF, but not by DTT. On the basis of the N-terminal sequence of the purified protease, the gene encoding the cold-adapted protease from J. lividum PAMC 25641 was cloned into the pET-28a(+) vector and heterologously expressed in Escherichia coli BL21(DE3) as an intracellular soluble protein.

• BMB Reports
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• v.31 no.4
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• pp.364-369
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• 1998

Insect plasma protein is abundant in the hemolymph of holometabolous insect larvae and is used as a source of amino acids and energy for construction of adult structures during metamorphosis. In order to understand the mechanism of decomposition of larval plasma proteins by hemocyte protease, we tried to purify a cysteine protease from the hemocyte lysate by using Carbobenzoxy-L-Phenylalanyl-L-Arginine-4-Methyl-Coumaryl-7-Amide (Z-Phe-Arg-MCA) as substrate and to identify plasma proteins that are selectively susceptible to the purified protease. Here, we describe the purification and characterization of a cysteine protease that specifically hydrolyzes the plasma protein of the coleopteran insect, Tenebrio molitor, larvae. The molecular mass of this enzyme was 25 kDa, as determined by SDS-PAGE under reducing conditions. The amino acids sequence of its $NH_{2}-terminus$ was determined to be Leu-Pro-Gly-Gln-Ile-Asp-Trp-Arg-Asp-Lys-Gly. This sequence contained Pro, Asp, and Arg residues, conserved in many papain superfamily enzymes. The specific cysteine protease inhibitors, such as E-64 and leupetin, inhibited its hydrolytic activity. One plasma protein with a molecular mass of 48 kDa was selectively hydrolyzed within 3 h when the purified enzyme and plasma proteins were incubated in vitro. However, the 48 kDa protein was not hydrolyzed by the purified 25 kDa protease in the presence of E-64. Western blotting analysis at various developmental stages showed that the purified enzyme was detected at larvae, pupae, and adult stages, but not the embryo stage.

• Journal of Microbiology
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• v.37 no.4
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• pp.213-217
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• 1999

An extracellular endopeptidase from Bacillus cereus SH-7 was purified to homogeneity. The protease was most active at pH 8 and $40{\circ}C$, respectively. The molecular mass of the protease was 40 kDa on SDS-PAGE, and 120 kDa by gel filtration, suggesting that the native enzyme is composed of three homogeneous subunits. The $K_m\;and\;V_{max}$ values of the protease for N-succinyl-$(Ala)_2$-Pro-Phe-p-nitroanilide were 11.11 mM and 170 nmol/mg of protein/min, respectively. The protease was also identified as a metalloprotease. The bioactivity of the SH-7 protease will need further study in the future.

• Food Science of Animal Resources
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• v.29 no.2
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• pp.157-163
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• 2009

This study was conducted for the isolation, purification, and characterization of a protease from Korean pear, to see its proteolytic activity on chicken actomyosin and to find the optimum pH and temperature of activity on chicken actomyosin. The protease was isolated from crude extract of Korean pear by ammonium sulfate precipitation. Further purification was done by DEAE-Sepharose ion-exchange chromatography, Mono-Q and Mini-Q column chromatography. The purified enzyme gave a single protein band on SDS polyacrylamide gel electrophoresis and the molecular weight was found to be 38 kDa. The specific activity of purified enzyme was 34,907 unit/mg with 25 fold purification and the yield was 2%. The purified enzyme incubated with chicken actomyosin showed high activity. The optimum pH and temperature for enzyme activity on chicken actomyosin were 6.5 and $70^{\circ}C$, respectively. A protease was purified from Korean pear for the first time and characterized. It was found to be promising for meat tenderization.

• Microbiology and Biotechnology Letters
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• v.18 no.4
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• pp.344-351
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• 1990

An alkalophilic microoganism producing a detergent-resistant alkaline protease was isolated from soil and identified as Baeiltus sp. The alkaline protease has been partially purified by ammonium sulfate fractionation, DEAE-Cellulose, CM-Cellulose and Sephdex G-100 column chromatography. The purified alkaline protease was highly active at pH 12-13 toward casein and stable at pH values from 6 to ll. The optimum temperature for the enzyme reaction was $55^{\circ}C$. The enzyme was completely inactivated by diisopropyl fluorophosphate (DFP) indicating that the enzyme was serine protease, but considerabiy stable in the presence of surface active agents.