• Korean Journal of Agricultural Science
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• v.47 no.3
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• pp.459-470
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• 2020

This study investigated the effects of the proteolytic hydrolysates of α-lactalbumin (LA), β-lactoglobulin (LG) and bovine serum albumin (BSA) by alcalase on inflammatory cytokines. The proteolytic hydrolysates were separated into two fraction of peptides, ≤ 10,000 Da and > 10,000 Da, respectively, because various low molecular weight peptides were generated during the hydrolysis reaction time. Among the hydrolysate peptides, BSA (all types), β-LG (> 10,000 Da), and α-LA (> 10,000 Da) showed an inhibitory activity against thymic stromal lymphopoietin (TSLP) mRNA expression in lipopolysaccharide-induced RAW264.7 murine macrophages. α-LA (> 10,000 Da), β-LG (hydrolysates), and BSA (> 10,000 Da) showed an inhibitory activity against tumor necrosis factor (TNF)-α expression. α-LA (all types), β-LG (hydrolysates, > 10,000 Da), and BSA (> 10,000 Da) showed an inhibitory activity against interleukin-6 (IL-6) expression. α-LA (> 10,000 Da), β-LG (> 10,000 Da), and BSA (all types) showed an inhibitory activity against inducible nitric oxide synthase (iNOS) expression. α-LA (> 10,000 Da), β-LG (> 10,000 Da), and BSA (all types) showed an inhibitory activity against cyclooxygenase (COX)-2 expression. The lowest level of TNF-α production was measured with α-LA (> 10,000 Da) and β-LG (> 10,000 Da) for all types, and a similar low level was measured for all types of BSA. The highest level of IL- 6 production was measured with α-LA (≤ 10,000 Da) among α-LA, β-LG, and IL-6. The low level of NO production was similar with α-LA, β-LG, and BSA but not with α-LA (≤ 10,000 Da). These potential peptides from whey protein hydrolysates could be used for food, medicinal, and industrial applications.

• The Korean Journal of Food And Nutrition
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• v.8 no.1
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• pp.37-42
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• 1995

The amino acid sequence of basic isozyme 55 of Horseradish Peroxidase (HRP E5) was determined by protein sequencing. HRP E5 consisted about 300 residues, and has a molecular weight of approximately 36,000 $\pm$ 500 dalton. The protein was rich In aspartic acid (14%), arginine(13%), and leucine(11%). The primary structure of HRP E5 was established by sequencing its tryptic (T1-T19) and lysylendopeptic (Al-A3) peptides. The sequence homology between HRP E5 and HRP C (neutral isozyme of horseradish peroxidase) is found to be more than 66%. The highest concentration of identical residues are found on residues 29~56, 90~123, and 155~173, but relatively low on 174~271.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.4
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• pp.488-494
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• 1999

Hydrolytic peptides of salted and fermented anchovy sauce, and anchovy actomyosin for the development of a rapid fermentation method with conventional tastes and flavors were studied. The optimal temperatures of crude enzymes isolated from anchor, liver and viscera of squid were 55, 40$\~$45 and $45\~60^{\circ}C$, respectively. Crude enzyme isolated from anchovy was more effective on hydrolysis of anchovy actomyosin than that from squid liver and viscera. But the crude enzyme from squid liver was less effective on NaCl than that from anchovy. Three peptides occurred in anchovy actomyosin hydrolyzed with crude enzymes from anchovy and squid liver for 30 min. Their molecular weight were determined by Superdex 200 gel chromatography as 10,800, 5,800 and 2,600 dalton. When anchovy sauce was hydrolyzed with crude enzymes of anchovy, squid liver and viscera, and Protamex during 70 days, ranges of their low molecular weight of hydrolyzed peptides were 300$\~$1,000dalton detected by Sephadex G-50 and their major amino acid compositions were glutamic acid, glycine and alanine, which was related with conventional tastes. Those amino acid compositions were similar to those of anchovy sauce hydrolyzed with squid liver, In the case of Protamex treatment, hydrolyzed peptides had high levels of isoleucine and leucine, being associated with the bitter, but a low level of glutamic acid.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.8
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• pp.1124-1129
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• 2005

Functional activities of low molecular weight substances purified from pepsin hydrolysates of four different seaweeds; Costaria costata, Enteromorpha prolifera, Grateloupia filicina and Porphyra tenera, were inves-tigated. Each pepsin hydrolysate of Costaria costata, Enteromorpha prolifera, and Grateloupia filicina resulted in three peptide peaks on Bio-Rad P2 gel chromatography pattern, while that of Porphyra tenera showed 2 peaks. Peak 1 of Porphyra tenera showed the highest antioxidative activity followed by peak 2 of Porphyra tenera and peak 2 of Costaria costata in order Peak 1 of Porphyra tenera showed the highest ACE inhibitory activity followed by peak 3 and peak 2 of Enteromorpha prolifera in order. Peak 1 and peak 2 of Porphyra tenera, and peak 2 of Enteromorpha prolifera showed the highest antityrosinase activity followed by peak 3 of Enteromorpha prolifera. Peak 1 of Enteromorpha prolifera showed the highest antitumor activity followed by peak 2 of Costaria costata, peak 3 of Enteromorpha prolifera, and peak 3 of Grateloupia filicina in order. Porphyra tenera showed the highest functional activities, which is thought to be due to its high protein content. Structure and amino acid sequence of low molecular weight peptide of Porphyra tenera should be analyzed in the further study.

• Korean Journal of Pharmacognosy
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• v.33 no.1 s.128
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• pp.21-28
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• 2002

Antidiabetic effects of the acid hydrolysate of silk fibroin were investigated by oral administration to animal models for diabetes mellitus, Fibroin protein was extracted from cocoon and digested to peptides of low-molecular weight range (mainly below 3,000) and amino acids by acid hydrolysis, Feeding of the fibroin hydrolysate resulted in a significant recovering effect on reduction of body weight gain and a lowering effect on blood glucose gain in streptozotocin-induced diabetic Sprague Dawley rats (STZ rats) which were used as an insulin-dependent diabetic animal model. But the body weight and blood glucose level in C57BL/KsJ-db/db mice (db/db mice), an non-insulin-dependent diabetic animal model, were not changed significantly by the feeding, On the other hand, plasma leptin levels increased according to increased feeding amount of the hydrolysate in STZ rats and db/db mice in common, It was concluded from the results that the fibroin hydrolysate might stimulate the insulin secretion by recovering or activating pancreatic ${\beta}$ cells and result in the increased plasma leptin level. It was also deduced that the antidiabetic improvements in body weight and blood glucose gain in STZ were thought to be due to the increased insulin secretion, but in db/db mice of which the diabetic symptoms were caused by insulin resistance, the stimulated secretion of insulin was unlikely to be able to change body weight and blood glucose level significantly.

• Korean journal of food and cookery science
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• v.24 no.3
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• pp.349-357
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• 2008

In an effort to augment extractability of carnosine and anserine at the levels of pro-oxidants such as iron and protein in Tuna boiled extracts(Skipjack, Yellowfin and Bigeye), we assessed the effects of heated and ion exchange chromatography(IEC) and ultrafiltration(UF) using a MW 500 cut-off(500 MWCO). We also evaluated the antioxidant activity of these extracts processed as free radical scavengers and reducing agents. Tuna boiled extracts of dark and ordinary muscle protein and total iron were reduced, whereas carnosine and anserine concentrations and antioxidant activity were increased. The carnosine and anserine concentrations of the ion exchange and permeate UF(IEC-UF) extracts were higher than those observed in the heated and permeate UF(heat-UF), whereas the protein and total iron contents were lower than that observed in the heat-UF. The quantity of carnosine and anserine in ordinary muscle was higher than that detected in dark muscle. HPLC analysis and SDS-PAGE were shown to removes the effect of UF on high molecular weight impurities in the tuna boiled extracts. The major free amino acids(FFAs) from Skipjack, Yellowfin and Bigeye tuna IEC-UF extracts were anserine, histidine and carnosine. These three peptides constituted more than 80～85%. of the detected amino acid. The IEC-UF treated ordinary muscle extracts evidenced the highest levels of DPPH radical scavenging activity and the highest levels of reducing power among the various extracts. The IEC-UF extracts evidenced a DPPH radical scavenging effect equal to that of 1mM ascorbic acid.

• Fisheries and Aquatic Sciences
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• v.18 no.1
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• pp.13-20
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• 2015

Calculated chemical scores (computed in relation to the FAO/WHO reference protein) for salmon liver protein hydrolysates indicated that all amino acids (other than methionine and threonine) were present in adequate or excess quantities; thus, the raw liver material is a good source of essential amino acids. The hydrophobic amino acids contents in hydrolysates prepared from Oncorhynchus keta and O. gorbuscha were 38.4 and 39.1%, respectively. The proportion of released peptides exceeding 500 kDa was reduced when hydrolysates were treated with the commercial enzyme Alcalase, although proportions in the following MW ranges were elevated: 100-500 kDa and <50 kDa. The optimal conditions for enzymatic hydrolysis were as follows: pH 7.0, $50^{\circ}C$, and a reaction time of 1 h. Of the different proteases tested, Alcalase was the most efficient for production of salmon liver hydrolysate with the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity. The hydrolysates prepared from salmon liver had a balanced amino acid composition. The liver protein hydrolysates contained low molecular weight peptides, some of which may be bio-active; this bio-active potential should be investigated. Inhibition of the DPPH radical increased with increased degree of hydrolysis (DH), regardless of protease type. DPPH radical scavenging abilities, antithrombotic effects and ${\alpha}$-glucosidase enzyme inhibition effects of O. keta liver hydrolysate increased in a dose-dependent manner. Thus, salmon liver hydrolysate may be useful in functional food applications and as a source of novel products.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.11a
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• pp.69-80
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• 1994

Although ureases play important roles in microbial nitrogen metabolism and in the pathogenesis of several human diseases, little is known of the mechanism of metallocenter biosynthesis in this Ni-Containing enzyme. Klebsiella aerogenes urease apo-protein was purified from cells grown in the absence of Ni. The purified apo-enzyme showed the same native molecular weight, charge, and subunit stoichiometry as the holo-enzyme. Chemical modification studies were consistent with histidinyl ligation of Ni. Apo-enzyme could not be activated by simple addition of Ni ions suggesting a requirement for a cellular factor. Deletion analysis showed that four accessory genes (ureD, ureE, ureF, and ureG) are necessary for the functional incorporation of the urease metallocenter. Whereas the $\Delta$ureD, $\Delta$ureF, and $\Delta$ureG mutants are inactive and their ureases lack Ni, the $\Delta$ureE mutants retain partial activity and their ureases possess corresponding lower levels of Ni. UreE and UreG peptides were identified by SDS-polyacrylamide gel comparisons of mutant and wild type cells and by N-terminal sequencing. UreD and UreF peptides, which are synthesized at ve교 low levels, were identified by using in vitro transcription/translation methods. Cotransformation of E. coli cells with the complementing plasmids confirmed that ureD and ureF gene products act in trans. UreE was purified and characterized. immunogold electron microscopic studies were used to localize UreE to the cytoplasm. Equilibrium dialysis studies of purified UreE with $^{63}$ NiC1$_2$ showed that it binds ～6 Ni in a specific manner with a $K_{d}$ of 9.6 $\pm$1.3 $\mu$M. Results from spectroscopic studies demonstrated that Ni ions are ligated by 5 histidinyl residues and a sixth N or O atom, consistent with participation of the polyhistidine tail at the carboxyl termini of the dimeric UreE in Ni binding. With these results and other known features of the urease-related gene products, a model for urease metallocenter biosynthesis is proposed in which UreE binds Ni and acts as a Ni donor to the urease apo-protein while UreG binds ATP and couples its Hydrolysis to the Ni incorporation process.ouples its Hydrolysis to the Ni incorporation process.s.

• BMB Reports
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• v.34 no.3
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• pp.201-205
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• 2001

Thionins are a family of low molecular weight cysteine-rich antimicrobial peptides. We isolated a cDNA encoding thionin gene from a flower bud cDNA library of Chinese cabbage (CFT). The gene contains 611 by nucleotides with 60 bp, and 150 by untranslated regions at its N- and C-terminal, respectively. The deduced amino acid sequence encoded 133 amino acids containing precursor polypeptide. The protein reveals that the precursor has a tripartite structure: a putative signal sequence at the N-terminus, followed by a mature thionin peptide, and a C-terminal acidic domain, which facilitates transport of the mature thionin through membrane. Genomic Southern blot analysis suggests that the CFT gene may be present as a single or two copy gene in the Chinese cabbage genome. Northern blot analysis shows that the gene is specifically expressed in flowers, but not in leaves, stems, or roots. When we analyzed the antifungal activity of the recombinant CFT protein, which was expressed in E. coli using the truncated cDNA region corresponding to the mature protein part, it was not active on fungal growth inhibition.

• Journal of Integrative Natural Science
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• v.10 no.3
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• pp.154-161
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• 2017

An antimicrobial peptides-producing Bacillus strain CBS73 was isolated from fermented food (kimchi) that produces low-molecular-weight proteins with broad-spectrum antimicrobial activity. Our goal was to explore the therapeutic potential of antimicrobial substances produced by Bacillus species. Peptide CBS73 was purified from Bacillus subtilis subsp. subtilis with identity of 99.79%. It was found to be stable at pH 4.0-10.0 and temp $20-60^{\circ}C$. A protein band around 5.2 kDa was detected in tricine-SDS-PAGE and band was confirmed by MALDI-TOF test. Peptide CBS73 showed antimicrobial activity against MDR bacteria. The minimal inhibitory concentration (MIC) of peptide CBS73 for vancomycin-resistant S. aureus (VRSA), vancomycin resistant Enterococci (VRE) and Salmonella typhimurium ranged from $10-40{\mu}g/mL$. The antioxidant activity of peptide CBS73 was measured by DPPH scavenging, reducing power activity and total phenolic content. Cell viability and NO production result showed less cytotoxic effect upto $12{\mu}g/mL$. Peptide CBS73 could be a promising antimicrobial agent for clinical application.