• Bulletin of the Korean Chemical Society
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• v.30 no.3
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• pp.582-588
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• 2009

Direct electron transfer of hemoglobin (Hb) in the chitosan (CTS) and $TiO_2$ nanoparticles (nano-$TiO_2$) composite films was achieved by using a room temperature ionic liquid of 1-butyl-3-methylimidazolium hexafluorophosphate ($BMIMPF_6$) modified carbon paste electrode (CILE) as the basal electrode. UV-Vis and FT-IR spectroscopy indicated that Hb in the film retained the native structure. Electrochemical investigation indicated that a pair of well-defined quasi-reversible redox peaks of Hb heme Fe(III)/Fe(II) was obtained with the formal potential located at -0.340 V (νs. SCE) in pH 7.0 phosphate buffer solution (PBS). The electrochemical parameters such as the electron transfer coefficient (α), the electron transfer number (n) and the standard electron transfer rate constant ($k_s$) were got as 0.422, 0.93 and 0.117 $s^{-1}$, respectively. The fabricated CTS/nano-$TiO_2$/Hb/CILE showed good electrocatalytic ability to the reduction of trichloroacetic acid (TCA) and hydrogen peroxide ($H_2O_2$), which exhibited a potential application in fabricating a new kind of third generation biosensor.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.475-481
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• 2013

By using ionic liquid 1-hexylpyridinium hexafluorophosphate ($HPPF_6$) based carbon ionic liquid electrode (CILE) as the substrate electrode, a $CoMoO_4$ nanorods and myoglobin (Mb) composite was casted on the surface of CILE with chitosan (CTS) as the film forming material to obtain the modified electrode (CTS/$CoMoO_4$-Mb/CILE). Spectroscopic results indicated that Mb retained its native structures without any conformational changes after mixed with $CoMoO_4$ nanorods and CTS. Electrochemical behaviors of Mb on the electrode were carefully investigated by cyclic voltammetry with a pair of well-defined redox peaks from the heme Fe(III)/Fe(II) redox center of Mb appeared, which indicated that direct electron transfer between Mb and CILE was realized. Electrochemical parameters such as the electron transfer number (n), charge transfer coefficient (${\alpha}$) and electron transfer rate constant ($k_s$) were estimated by cyclic voltammetry with the results as 1.09, 0.53 and 1.16 $s^{-1}$, respectively. The Mb modified electrode showed good electrocatalytic ability toward the reduction of trichloroacetic acid in the concentration range from 0.1 to 32.0 mmol $L^{-1}$ with the detection limit as 0.036 mmol $L^{-1}$ ($3{\sigma}$), and the reduction of $H_2O_2$ in the concentration range from 0.12 to 397.0 ${\mu}mol\;L^{-1}$ with the detection limit as 0.0426 ${\mu}mol\;L^{-1}$ ($3{\sigma}$).

• Food Science of Animal Resources
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• v.43 no.2
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• pp.305-318
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• 2023

This study investigated the protein digestibility of chicken breast and thigh in an in vitro digestion model to determine the better protein sources for the elderly in terms of bioavailability. For this purpose, the biochemical traits of raw muscles and the structural properties of myofibrillar proteins were monitored. The thigh had higher pH, 10% trichloroacetic acid-soluble α-amino groups, and protein carbonyl content than the breast (p<0.05). In the proximate composition, the thigh had higher crude fat and lower crude protein content than the breast (p<0.05). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of myofibrillar proteins showed noticeable differences in the band intensities of tropomyosin α-chain and myosin light chain-3 between the thigh and breast. The intrinsic tryptophan fluorescence intensity of myosin was lower in the thigh than in the breast (p<0.05). Moreover, circular dichroism spectroscopy of myosin revealed that the thigh had higher α-helical and lower β-sheet structures than the breast (p<0.05). The cooked muscles were then chopped and digested in the elderly digestion model. The thigh had more α-amino groups than the breast after both gastric and gastrointestinal digestion (p<0.05). SDS-PAGE analysis of the gastric digesta showed that more bands remained in the digesta of the breast than that of the thigh. The content of proteins less than 3 kDa in the gastrointestinal digesta was also higher in the thigh than in the breast (p<0.05). These results reveal that chicken thigh with higher in vitro protein digestibility is a more appropriate protein source for the elderly than chicken breast.

• Food Science of Animal Resources
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• v.44 no.2
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• pp.430-442
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• 2024

This research aimed to assess the effect of collagenolytic proteases from Bacillus subtilis B13 and Bacillus siamensis S6 for tenderizing goat meat during wet aging. Collagenolytic proteases B13 and S6 were prepared at 5 U/mL of collagenolytic activity before injecting into goat meat with 10% (v/w) of initial weight. The control sample was injected with distilled water and used as a negative control. The injected meats were placed in vacuum-sealed bags and wet aged at 4℃ for 0, 3, 5, 7, 14, and 21 days. Thereafter, total aerobic count and physicochemical quality were elucidated. Both enzyme-treated samples from B13 and S6 aged for 5 days showed an acceptable microbial quality with lower than 5.7 Log CFU/g. These conditions produced the tender meats by the reduction in shear force accounting for 30% for B13 and 26% for S6 as compared to the control. Moreover, the enzyme-treated samples showed lower values of hardness, gumminess, and chewiness, with higher springiness and trichloroacetic acid-soluble peptides than the control (p<0.05). The detrimental impact on cooking loss and lipid oxidation was not found. Enzyme-injected meat had a lower cooking loss than the control (p<0.05) with no significant difference in lipid oxidation (p>0.05). Notably, meats treated with B13 and S6 were lower in CIE L^* value as compared to the control (p<0.05) with no significant impact on CIE a^* and CIE b^* (p>0.05). These results suggested that these two collagenolytic proteases could enhance the quality of goat meat in terms of tenderness and reduce the aging time for meat tenderization.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.1
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• pp.51-57
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• 2014

Purpose: The present study was conducted to establish the experimental condition for the proper evaluation of protein removal efficacy when developing protein removal agents. Its protein removal efficacy was further analyzed and compared with the result from protein removal efficacy against protein deposition on contact lens to suggest the evaluation method for efficacy of protein removal agents. Methods: Protein digestibility assay presented in the Korean pharmacopoeia was selected to establish the evaluation method for efficacy of papain, pancreatin, subtilisin A and protease itself as a ingredient and protein removal tablets or solution containing those enzymes and find a suitable test conditions. Furthermore, the cleaning efficacy of commercially available protein removal tablets and solution on balafilcon A lens deposited with protein artificially was measured and the correlation between two evaluation methods was further analyzed. Results: When pancreatin itself and the product containing pancreatin was evaluated by protein digestibility assay, both reached 28 IU/mg, the standard value of protein digestibility suggested by the Korean pharmacopoeia. In case of protease and subtilisin A tested with trichloroacetic acid B solution, both of them met the enzyme activity level proposed by the manufacturers when they were evaluated by protein digestibility assay however, papain and subtilisin A tested with trichloroacetic acid A solution were not reached the enzyme activity level. Among protein removal agents, three products except a product containing pancreatin did not meet the enzyme activity value specified by the manufacturer when they were evaluated by protein digestibility assay. However, actual protein removal efficacy of three products except a papain-containing product on the lens was greater than 90% protein removal. In the case of papain-containing protein removal product, its effect was not measured by protein digestibility assay however, its actual protein removal efficacy on the lens reached 73.72%. Conclusions: From the results, it was confirmed that the efficacy of protein removal agents for contact lens should be evaluated by different method according to the type of proteolytic enzyme contained. That is, the protein removal agents containing pancreatin, protease and subtilisin A can be evaluated by protein digestibility assay and protein removal efficiency evaluation and the products containing papain can be effectively evaluated by only the evaluation method for protein removal efficiency employing the lens.

• Food Science and Preservation
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• v.16 no.5
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• pp.705-713
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• 2009

We prepared salmon patties and compared the quality characteristics thereof with those of commercial tuna and pork patties. The moisture and crude ash contents of salmon patty were lower, whereas the crude protein content was higher, than those of commercial patties. The crude lipid content of salmon patty was higher than that of tuna patty, but lower than that of pork patty. The pH value and the volatile basic nitrogen content of salmon patty were lower than those of the commercial patties. Hunter color values (L, a, b) in a cross-section of cooked salmon patty were higher, whereas the ${\Delta}E$ value was lower, than those of the two commercial patties. The lipophilic browning index (0.397) of salmon patty was higher, whereas the hydrophilic browning index (0.047) was lower, than those of commercial patties. Trichloroacetic acid-soluble N content (272 mg/100 g) of salmon patty was lower than of commercial patties. The major fatty acids of salmon patty were palmitic acid (11.9%), oleic acid (27.6%), and linoleic acid (30.1%), whereas small amounts of eicosapentaenoic acid (EPA, 3.7%) and docosahexaenoic acid (DHA, 8.4%) were also found. The predominant amino acids of all patties were arginine, glutamic acid, aspartic acid, leucine, threonine, and proline, and the contents of these amino acids in salmon patty were higher than in the two commercial patties. The Fe, Ca, K, P, and Mg contents of salmon patty were 2.4 mg/100g, 42.6 mg/100g, 207.5 mg/100g, 211.6 mg/100 g, and 29.9 mg/100 g, respectively. The sensory quality of salmon patty was higher than that of pork patty. These results indicate that salmon patty may have good quality characteristics, comparable to those of the two commercial patties.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.1
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• pp.38-41
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• 2005

An experiment was conducted on 3 male rumen fistulated adult buffaloes fed on wheaten straw and concentrate mixture in a Latin square design to study the impact of niacin supplementation on rumen metabolites. Three animals were fed wheaten straw+concentrate mixture (group I, control), wheaten straw+concentrate mixture+100 ppm niacin (group II), and wheaten straw +concentrate mixture+200 ppm niacin (group III). After 21 days feeding, rumen liquor was drawn for 3 consecutive days at different time intervals (0, 2, 4, 6 and 8 h) to study the various rumen metabolites i.e., rumen pH, ammonia-N, total-N, trichloroacetic acid precipitable-N, non-protein nitrogen, total volatile fatty acids, their fractions and number of protozoa. Mean pH values in strained rumen liquor (SRL) of animals in 3 groups were 6.64, 6.71 and 6.67, indicating no statistically significant difference. Results revealed a significant (p<0.01) increase in TVFA concentration among the supplemented groups (group II and III) in comparison to control group. Mean TVFA concentration (meq/dl) was 9.75, 10.97 and 11.44 in 3 groups respectively. The highest concentration of TVFA was observed at 4 h and minimum at 0 h in all the 3 groups. The percentage of acetic, propionic, butyric and isobutyric acid was statistically similar among the three groups. The mean ammonia-N concentration (mg/dl SRL) was significantly (p<0.01) lower in group II (16.38) and group III (15.42) than group I (18.14). Ammonia-N concentration was higher (p<0.01) at 4 h as compared to all the time intervals. The mean total-N concentration (mg/dl SRL) was higher (p<0.01) in group II (74.16) and group III (75.47) as compared to group I (62.04). Total-N concentration was higher (p<0.01) at 4 h as compared to other time intervals and lowest value was recorded at 0 h.Concentration of TCA-ppt-N (mg/dl SRL) was significantly (p<0.01) lower in control group as compared to niacin supplemented groups. Mean value of NPN (mg/dl SRL) was significantly (p<0.01) lower in group III (23.21) as compared to group I (25.71), whereas groups I and II, and groups II and III were similar to each other. Total protozoa number (${\times}10^4$/ml SRL) ranged from 18.06 to 27.41 in group I, 20.89 to 38.44 in group II and 27.61 to 39.45 in group III. The mean protozoa number was significantly (p<0.01) higher in SRL of group II (27.60) and III (30.59) as compared to group I (22.48). It can be concluded from the study that supplementation of niacin in the diet of buffaloes had improved the rumen fermentation by decreasing the concentration of ammonia-N and increasing protein synthesis.

• Journal of the Korean Society of Food Science and Nutrition
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• v.10 no.1
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• pp.85-91
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• 1981

The growing cells of S. aureus were fractionated along the Schmidt-Thannhauser-Schneider's technique into several fractions such as TCA(trichloroacetic acid)-soluble, lipid, nucleic acid, protein and residue fraction. They were also fractionated according to their cellular structure into Sonic-supernatant, SDS(sodium lauryl sulfate)-soluble, Formamide-soluble and Residue fraction. Fractionation was carried out by orderly treatment of the Sonic pellet with 1.0% SDS and hot$(150^{\circ}C)$ formamide, and the pellet was prepared by centrifugation of the cells sonic osillated for 20 minutes at 150 watt. Sonic-supernatant fraction contained a 91.3% of total DNA while other fractions contained less than 9.5%. SDS-soluble fraction showed a high activity of malate dehydrogenase(13.67 unit/mg protein) and which was higher 22.3 times than the activity found from unsoluble fraction. Formamide-soluble fraction prepared from SDS-undoluble pellet by using the hot formamide exhibited a clear action of reducing sugars against the Anthronesulfate, while it exhibited no clear action against the ninhydrin. However, contrastly, the residue remainnning after extraction with formamide exhibited a clear action against ninhydrin and glucosamine was detected form the hydrolysate of residue by paper chromatography. From these results it is considered that the Sonic-supernatant fraction is mainly consisted of plasmic component of the cells. Other fractions, SDS-soluble, Formamide-soluble and Residue, should be consisted of plasma membrane, lipoplysaccharide and peptidoglycan of the cell, respectively.

• Journal of Pharmaceutical Investigation
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• v.35 no.2
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• pp.117-122
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• 2005

After establishing improved HPLC analytical method of cefaclor in human plasma samples, a bioavailability study of cefaclor capsules was conducted according to the guidelines of Korea Food and Drug Administration (KFDA). The standard calibration curve using an HPLC with UV detector was constructed in a range of $0.0324{\sim}16\;{\mu}g/ml$. The 6% perchloric acid instead of 6% trichloroacetic acid was used to precipitate plasma protein. The HPLC chromatograms were precisely and accurately resolved when spiked with human plasma spiked with cefaclor and cephalexin (internal standard). Twenty healthy male Korean volunteers received two commercial cefaclor capsules, $Neocef^{\circledR}$ capsule (Jinyang Pharm. Co., Ltd) or $Ceclor^{\circledR}$ capsule (Lilly Korea. Co., Ltd.) at the 250 mg cefaclor in a $2{\times}2$ crossover study. There was a one-week washout period between the doses. Plasma concentrations of cefaclor were monitored for 8 hours after oral drug administration. $AUC_t$ the area under the plasma concentration-time curve from time zero to 8 hr (13 points), was calculated by the linear trapezoidal rule method. $C_{max}$ (maximum plasma drug concentration) and $T_{max}$ (time to reach $C_{max}$) were compiled from the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed $AUC_t$ and $C_{max}$. No significant sequence effect was found for all of the bioavailability parameters indicating that the cross-over design was properly performed. The 90% confidence intervals of the $AUC_t$ ratio and the $C_{max}$ ratio for $Neocef^{\circledR}/Ceclor^{\circledR}$ were $0.9049{\leq}{\delta}{\leq}1.226$, respectively. These values were within the acceptable bioequivalence intervals of 0.80-1.25. Thus, our study demonstrated the bioequivalence of $Neocef^{\circledR}/Ceclor^{\circledR}$ with respect to the extent of absorption.

• Journal of Environmental Health Sciences
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• v.40 no.2
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• pp.114-126
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• 2014

Objectives: We aimed to develop a measurement method of five metabolites of trichloroethylene (TCE) in a concurrent biological sample, e.g., trichloroacetic acid (TCA), dichloroacetic acid (DCA), S-(1,2-dichlorovinyl) glutathione (DCVG), S-(1,2-dichlorovinyl)-L-cysteine (DCVC), and N-Acetyl-S-(1,2-dichlorovinyl)-L-cysteine (NAcDCVC) and to validate the method before application to pharmacokinetic study. Methods: TCE metabolites were simultaneously analyzed using high performance liquid chromatography coupled with electrospray ionization mass spectrometry (HPLC-ESI-MS/MS) with as little as 50 ${\mu}L$ of serum and urine. DCA, TCA and NAcDCVC were extracted with diethyl ether, while DCVC and DCVG were extracted by solid phase extraction. This method was validated according to the guidelines for bioanalytical method validation of the Korean National Institute of Toxicological Research. Then, we determined the five metabolites in five strains of mice at 24 hr after exposure to 1 g TCE /kg body weight. Results: The limits of detection for the five metabolites in biological samples ranged from 0.001 to 0.076 nmol/mL, which is comparable to or better than those previously reported. Most calibration curves showed good linearity ($R^2=0.99$), and between-batch variation was less than 20% expressing acceptable robustness and reproducibility. Using this method, we found TCA and DCA were detected in all test mice at 24 hr after the oral administration while NAcDCVC and DCVC were detected in some strains, which showed strain-dependent metabolism of TCE. Conclusions: The present method could provide robust and accurate measurements of major key metabolites of TCE in biological media, which allowed concurrent analysis of TCE metabolism for limited amounts of biospecimens.