• International Journal of Industrial Entomology and Biomaterials
• /
• v.31 no.1
• /
• pp.30-33
• /
• 2015

Enzymatic modification of proteins is often used to increase the biological activity of materials. Silkworm powder has been investigated as a functional food resource, but no study has been performed on its modification by commercial food enzyme. Therefore, this study aimed to determine the feasibility of such modification of silkworm powder by alkaline protease. The activity of the enzyme was confirmed using an azocasein assay. Subsequently the silkworm powder was hydrolyzed by enzymatic treatment. UV visible spectrometry showed that the supernatant of silkworm powder subjected to enzymatic treatment had a stronger absorption band than the untreated powder. SDS-PAGE electrophoresis showed that the molecular weight of silkworm powder decreased on enzymatic treatment. Thus the results indicate that commercial enzymes might be used to modify the characteristics of silkworm powder.

• Korean Journal of Food Science and Technology
• /
• v.24 no.4
• /
• pp.341-346
• /
• 1992

The antimutagenic effects of enzymatic browning reaction products (MEBRPs) of polyphenol compounds (catechol, homocatechol, hydroxyhydroquinone, pyrogallol) by enzyme extracted from mushroom (Agaricus bisporus) were demonstrated through spore rec-assay using B. subtilis $H17(rec^+)$ and $M45(rec^-)$, Ames test using S. typhimurium TA98 and TA100 and SOS chromotest using E. coli PQ37/plasmid pKM101. In spore rec-assay, the MEBRPs showed antimutagenic effects by decreasing of the inhibition zone induced by MNNG. In Ames test with S-9mix in both TA98 and TA100, all of MEBRPs showed strong antimutagenic effects of about 21 to 99% against mutation by $B({\alpha})P$ and Trp-P-1, as adding $300\;{\mu}l$ of the MEBRPs. In SOS chromotest, MEBRPs showed antimutagenic effects by inhibiting the SOS-inducing function induced by 4NQO and MMC, as increasing in concentration of the MEBRPs. But they did not showed mutagenicity in these bacterial assays.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.19 no.1
• /
• pp.98-101
• /
• 2005

Gamgung-tang(GGT) that is included in Gamdu-tang(consists of Glycyrrhizae Radix, black beans) and Gunggui-tang(consists of Angelicae Radix and Cnidii Rhizoma), showed therapeutic effects of autoimmume thyroiditis in the previous reports. GGT was tested for the safety using Rec assay and enzymatic methods. In the Rec assay, Bacillus subtilis H-17$(Rec^+)$ and M-45$(Rec^-)$ strains were used to test DNA damage activity. From the results, there was no DNA damage of GGT. Hepatotoxicity of GGT to female ICR mice was also monitored by the measurements of serum(s)-GOT, s-GPT and LDH activities after oral feeding for 15 days. GGT was not shown any significant changes of s-GOT, s-GPT and LDH activities in mice sera.

• Applied Biological Chemistry
• /
• v.35 no.2
• /
• pp.82-86
• /
• 1992

This research was carried out to investigate antimutagent effect of peach enzymatic browning reaction products(PEBRP) obtained by reacting each of polyphenol compounds with oxidase extracted from Korea-cultivated peach. In methods, rec-assay with B. subtilis strains $H17(rec^+)\;and\;M45(rec^-)$, and Ames test with S. typhimurium TA98 and TA100 were used. The spore rec-assay of PEBRP, pyrogallol, hydroxyhydroquinone, homocatechol and caffeic acid were not showed mutagenicity. In the effects of various metal ions$(Al^{3+},\;Cu^{2+},\;Fe^{2+},\;Mn^{2+},\;Ni^{2+},\;Pb^{2+},\;Zn^{2+})$ on the rec-assay, all PEBRP except caffeic acid was increased inhibition zone(5 mm) only with $Zn^{2+}$. In paticular, the Py-PEBRP was decreased the difference of inhibition zone of growth on MMC(mitomycin C). In results of Ames test, all PEBRP were not showed mutagenicity on S. typhimurium TA98 and TA100; however, Ca-PEBRP and Hca-PEBRP were suppressed mutagenic effects on Trp-P-1 and B(a)P in the presence of S-9Mix.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.19 no.3
• /
• pp.224-228
• /
• 1990

Cabbage contained high peroxidase activity among tested plant sources. The cabbage peroxi-dase can replace horseradish peroxidase to assay glucose with glucose oxidase. The amount of glucose can be determined quantitatively by glucose oxidase-cabbage peroxidase. The opti-mum pH and temperature for enzymatic glucose determination by glucose oxidase-cabbage peroxidase were 6.0 and 35-45$^{\circ}C$ respectively. The glucose assay was inhibited by addition of various metal salts such as mercuric chloride lead acetate silver nitrate ammonium molyb-date sodium tunstate and cupric sulfate. The relationship between absorbance and amount of glucose was linear up to 8.33 mM glucose in the assay mixture under the assay conditions.

• BMB Reports
• /
• v.52 no.10
• /
• pp.589-594
• /
• 2019

Single-molecule techniques have been used successfully to visualize real-time enzymatic activities, revealing transient complex properties and heterogeneity of various biological events. Especially, conventional force spectroscopy including optical tweezers and magnetic tweezers has been widely used to monitor change in DNA length by enzymes with high spatiotemporal resolutions of ~nanometers and ~milliseconds. However, DNA metabolism results from coordination of a number of components during the processes, requiring efficient monitoring of a complex of proteins catalyzing DNA substrates. In this min-review, we will introduce a simple and multiplexed single-molecule assay to detect DNA substrates catalyzed by enzymes with high-throughput data collection. We conclude with a perspective of possible directions that enhance capability of the assay to reveal complex biological events with higher resolution.

• Journal of Oral Medicine and Pain
• /
• v.39 no.4
• /
• pp.127-132
• /
• 2014

Purpose: Many substances in saliva or oral health care products interact with each other. The aim of this study was to investigate interactions between hyaluronic acid (HA), lysozyme, peroxidase, and glucose oxidase (GO) in enzymatic activities at low pH levels. Methods: HA (0.5 mg/mL), hen egg-white lysozyme (HEWL, $30{\mu}g/mL$), bovine lactoperoxidase (bLPO, $25{\mu}g/mL$), and GO ($50{\mu}g/mL$) were used. The influences of HA, bLPO, and GO on HEWL activity were determined by measuring the turbidity of a Micrococcus lysodeikticus suspension. The influences of HA and HEWL on bLPO activity were determined by the NbsSCN assay, measuring the rate of oxidation of 5-thio-2-nitrobenzoic acid (Nbs) to 5,5'-dithiobis(2-nitrobenzoic acid) $(Nbs)_2$. The influences of HA and HEWL on GO activity were determined by measuring oxidized o-dianisidine production. All experiments were performed at pH 4, 5, and 6. Results: HA and GO did not affect the enzymatic activity of HEWL at pH 4, 5, and 6. bLPO enhanced the enzymatic activity of HEWL at pH 5 (p<0.05) and pH 6 (p<0.05) significantly. The enzymatic activity of bLPO was not affected by HA and HEWL at pH 4, 5, and 6. HA and HEWL did not affect the enzymatic activity of the GO at pH 4, 5, and 6. Conclusions: Peroxidase enhances lysozyme activity at low pH, otherwise there were no significant interactions in enzymatic activities between HA, lysozyme, peroxidase, and GO at low pH levels.

• Journal of Microbiology and Biotechnology
• /
• v.26 no.1
• /
• pp.180-189
• /
• 2016

The widespread occurrence of drug-resistant Mycobacterium tuberculosis places importance on the detection of TB (tuberculosis) drug susceptibility. Conventional drug susceptibility testing (DST) is a lengthy process. We developed a rapid enzymatic color-reaction-based biochip assay. The process included asymmetric multiplex PCR/templex PCR, biochip hybridization, and an enzymatic color reaction, with specific software for data operating. Templex PCR (tem-PCR) was applied to avoid interference between different primers in conventional multiplex-PCR. We applied this assay to 276 clinical specimens (including 27 sputum, 4 alveolar lavage fluid, 2 pleural effusion, and 243 culture isolate specimens; 40 of the 276 were non-tuberculosis mycobacteria specimens and 236 were M. tuberculosis specimens). The testing process took 4.5 h. A sensitivity of 50 copies per PCR was achieved, while the sensitivity was 500 copies per PCR when tem-PCR was used. Allele sequences could be detected in mixed samples at a proportion of 10%. Detection results showed a concordance rate of 97.46% (230/236) in rifampicin resistance detection (sensitivity 95.40%, specificity 98.66%) and 96.19% (227/236) in isoniazid (sensitivity 93.59%, specificity 97.47%) detection with those of DST assay. Concordance rates of testing results for sputum, alveolar lavage fluid, and pleural effusion specimens were 100%. The assay provides a potential choice for TB diagnosis and treatment.

• Korean Journal of Food Science and Technology
• /
• v.29 no.2
• /
• pp.383-386
• /
• 1997

Maize starches with different amylose content were repeated autoclaving-cooling cycles up to 4 times, and the yield of resistant starch (RS) from autoclaved maize starches was investigated by enzymatic-gravimetric method and ${\alpha}-amylase$ treatment. With increasing amylose content in starch and the number of autoclaving-cooling cycles, RS yield was also increased, regardless of isolation method. Enzymatic-gravimetric method severely hydrolyzed amorphous region of autoclaved maize starches. Crystalline region was obtained more effectively by enzymatic-gravimetric method than by ${\alpha}-amylase$ treatment.

• BMB Reports
• /
• v.37 no.3
• /
• pp.339-342
• /
• 2004

Germination is a process which characterized with nescient synthesis of genes. Among the genes synthesized during the germination of wheat embryos, germin genes, proteins and their enzymatic activity were defined. Germin is a water soluble homopentameric glycoprotein which is remarkable resistant to degradation by a broad range of proteases including pepsin. Germin proteins found to have strong oxalate oxidase activity which produces hydrogen peroxide by degrading oxalic acid. The current study, aimed to localize the germin genes, proteins and enzymatic activities in developing coleoptiles which is a rapidly growing protective tissue of leaf primordium and shoot apex. Non-radioactively abeled germin riboprobes were employed to localize germin mRNAs in situ. FITC (Fluorescein isothiocyanate) and alkaline phosphatase linked anti-germin antibodies were used to localize germin proteins under the fluorescence and light microscopy and finally germin enzymatic activity was localized by using appropriate enzyme assay. The results revealed that in coleoptiles germin genes, proteins and their enzymatic activity were predominantly associated with the cells of epidermis and vascular bundle sheath cells.