• Proceedings of the PSK Conference
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• 2002.10a
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• pp.362.3-362.3
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• 2002

The Polyoxin complex is an antifungal antibiotics produced by Streptomyces cacaoi var. asoensis that exhibit marked and selective activity against pytopathogenic fungi. They incorporate carbamoylated dipeptides attached to the sugar moiety. Controlled alkaline hydrolysis of polyoxins result in several products. one of which has been identified as (＋)-(2S. 3S, 4S)-2-amino-3. 4. 5-trihydroxypentonic acid(polyoxamic acid). A variety of chemical syntheses of polyoxamic acid have been developed over several years. (omitted)

• Journal of Food Hygiene and Safety
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• v.35 no.5
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• pp.513-520
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• 2020

Here, we evaluated the functional properties of histidine-containing low-molecular-weight (LMW) peptides obtained from tuna waste meats. As with histidine-related components composed of histidine, 1-methyl histidine and anserine, histidine-containing LMW peptides exhibited high α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging effect in a dose-dependent manner. Among the histidine-related dipeptides, anserine exhibited the highest reducing power followed by carnosine. By comparison with dipeptides, tuna extracts also showed similar reducing power and the activity was in a dose-dependent manner. In addition, the antioxidant activities of tuna extracts such as DPPH radical scavenging effect, reducing power, superoxide dismutase activities, and peroxide value of linoleic acid were affected by the various extraction methods.

• Journal of the Korean Chemical Society
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• v.5 no.1
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• pp.33-37
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• 1961

We have shown that carboxy-peptidase destroys the biological activity of angiotensin octa-and deca-peptides. Since Proline occurs as the seventh amino acid from the amino end of the chain and since carboxypeptidase does not cleave proline from a peptid chain, it is evident that the heptapeptid H.asp-arg-val-tyr-ileu-his-pro.OH is formed by this hydrolysis. This peptide must then be biologically inactive. In order to determine whether the phenyl group of the C-terminal amino acid was the necessary requirement for biological activity of the octapeptide, $ala^8$ angiotensin octapeptide(amino acids of peptides numbered from amino end) was synthesized. For this synthesis the four dipeptides were prepared: carbobenzoxy-L-prolyl-L-alanine-P-nitrobenzyl-ester, m.p. $134-135^{\circ}C,$ carbobenzoxy-L-isoleucyl-imidazole benzyl-L-histidine methyl ester, m.p. $114-116^{\circ}C,$ carbobenzoxy-L-valyl-L-tyrosine hydrazide and carbobenzoxy B-benzyl-L-aspartyl-nitro-L-arginine. The first three dipeptides were obtained as crystalline compounds. Imidazole-benzyl-L-histidine was used in the hope that it would block the histidine imidazole against side reactions in steps subsequent to the formation of the C-terminal tetrapeptide. Also, it was through that the imidazole benzylated peptides would be easier to crystallize. This, however, was not the case. The tetrapeptide, carbobenzoxy-L-isoleucyl-L-im, benzyl-histidyl, L-prolyl-L-alanine-nitrobenzyl ester was not obtained in a crystalline form. Neither could the mono-or dihydrobromide of the tetrapeptide free base be induced to crystallize. Carbobenzoxy-L-valyl-L-tyrosine azide was condensed with the tetrapeptide free base to yield the protected hexapeptide; carbobenzoxy-L-valyl-L-tyrosyl-L-isoleucyl-L-im, benzyl, histidyl-L-Prolyl-L-alanine-nitrobenzyl ester. Upon removal of the carbobenzoxy group with hydrogen bromide in acetic acid an amorphous free base hexapeptide ester was obtained. This compound gave the correct C, H, N analysis and contained the six amino acids in the correct ratio. The octapeptide was obtained by condensing this hexapeptide with carbobenzoxy-B-benzyl-L-aspartyl-nitro, L-arginine using the mixed anhydride method of condensation. This amorphous product was proven to be homogenous by chromatography in two solvent systems and upon hydrolysis yielded the eight amino acids in correct ratio. The five protecting groups were removed from the octapeptide by hydrogenolysis over palladium black catalyst. Biological assay of the free peptide indicated that it possessed less than 0.1 per cent of both pressor and oxytocic activity of the phenylalanine8 angiotensin. This suggests that the phenyl group is a point of attachment between angiotensin and its biological receptor site.

• Journal of the Korean Chemical Society
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• v.19 no.5
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• pp.375-380
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• 1975

An enzyme capable of hydrolyzing histidylleucine was purified 50 fold from hog lung. The final preparation hydrolyzed $1.6{\mu}moles$ of histidylleucime per minute per mg of protein. The $K_m$ of the enzyme for the enzyme was found to be $2{\times}10^{-4}M$. The enzyme was required a number of free dipeptides for the substrate specificity, and was inhibited by EDTA and 1,10-phenan-throline. The molecular weight of the enzyme was estimated to be 80,000 daltons from sucrose density gradient sedimentation analysis. The corrected $s_{20,w}$ value was 5.3 S.

• BMB Reports
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• v.28 no.5
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• pp.451-457
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• 1995

Four carboxypeptidases, CP1, CP2, CP3, and CP4 were isolated from the cotyledons of germinating seedlings of Canavalia lineata by sequential chromatography on the following four columns: 1) CM-cellulose, 2) Sephacryl 5-300, 3) Procion red dye, and 4) Sephacryl S-200. A number of properties of the enzymes, such as substrate specificity, molecular weight, optimum pH, thermal stability, have been determined. Enzyme activities were measured using the Cbz(carbobenzoxy)-dipeptides containing phenylalanine at the penultimate position. The $K_m$ values of four carboxypeptidases for Cbz-Phe-Ala were 0.50, 0.65, 1.30, and 1.35 mM, respectively. The inhibition studies indicated that the four carboxypeptidases were all serine type. Each of the carboxypeptidases with molecular weights of 145, 114, 105, and 104 kDa, respectively, had the optimum enzyme activity at pH 5.0~6.0. And they were sensitive to high temperature.

• Journal of Pharmaceutical Investigation
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• v.23 no.3
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• pp.31-40
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• 1993

It is essential to clone the peptide transporter in order to obtain better understanding of its molecular structure, regulation, and substrate specificity. Characteristics of an endogenous peptide transporter in oocytes were studied along with expression of an exogenous proton/peptide cotransporter from rabbit intestine. And further efforts toward cloning the transporter were performed. The presence of an endogenous peptide transporter was detected in Xenopus laevis oocytes by measuring the uptake of $0.25\;{\mu}M\;(10\;{\mu}Ci/ml)\;[^3H]-glycylsarcosine$ (Gly-Sar) at pH 5.5 with or without inhibitors. Uptake of Gly-Sar in oocytes was significantly inhibited by 25 mM Ala-Ala, Gly-Gly, and Gly-Sar (p<0.05), but not by 2.5 mM of Glu-Glu, Ala-Ala, Gly-Gly, Gly-Sar and 25 mM glycine and sarcosine. This result suggests that a selective transporter is involved in the endogenous uptake of dipeptides. Collagenase treatment of oocytes used to strip oocytes from ovarian follicles did not affect the Gly-Sar uptake. Changing pH from 5.5 to 7.5 did not affect the Gly-Sar uptake significantly, suggesting no dependence of the endogenous transporter on a transmembrane proton gradient. An exogenous $H^+/peptide$ cotransporter was expressed after microinjection of polyadenylated messenger ribonucleic acid $[poly\;(A)^+-mRNA]$ obtained from rabbit small intestine. The Gly-Sar uptake in mRNA-injected oocytes was 9 times higher than that in water-injected oocytes. Thus, frog oocytes can be utilized for expression cloning of the genes encoding intestinal $H^+/peptide$ cotransporters. Using the technique size fractionation of mRNA was sucessfully obtained.

• KSBB Journal
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• v.9 no.1
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• pp.72-84
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• 1994

A model to explain the observed kinetics in a whole process of Cheddar-cheese ripening has been developed. It includes growth and lysis of cells in the cheese matrix, cell-wall bound protelnases and intracellular dipeptidases that are released into cheese upon cell lysis, and the production of dipeptides and amino acids from casein in cheese. Model simulations have been conducted to figure out the crucial factors in the process of the cheese ripening. The influential factors have been found to be the cell numbers and the dipeptidase activity at the beginning of the cheese ripening, and the cell-lysis rate of cheese starters. The simulation results have also suggested the use of a mixed culture as well as the experimental screening for a more suitable organism as a cheese starter hence, the model shows how to accelerate the cheese ripening.

• Bulletin of the Korean Chemical Society
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• v.27 no.8
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• pp.1211-1218
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• 2006

The enantiomerically pure (2R,3S)- and (2R,3R)-3-amino-2-hydroxy-4-phenylbutanoic acids (AHPBA) 1 and 3 are readily obtained from D-glucono-a-lactone. Both AHPBAs are the structural key units of KMI derivatives which are the potent inhibitors of BACE 1 ($\beta$-secretase) and HIV protease. Additionally, the obtained AHPBAs 1 and 3 are converted to dipeptides of bestatin stereoisomers 2 and 4.

• The Korean Journal of Food And Nutrition
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• v.26 no.1
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• pp.117-124
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• 2013

근내지방도(IMF)가 한우육의 품질 및 기능성분에 미치는 영향을 조사하기 위하여, 250두의 한우를 근내지방 함량에 따라 Low(<14%, n=96), Medium(14~17%, n=83), High(>17%; n=71) 세 그룹으로 분류하고, 7일간 숙성 후 등심육의 품질 및 기능성분을 분석하였다. 한우 등심육의 수분 함량은 IMF와 반비례하였으며, High IMF 그룹은 Low IMP 그룹에 비하여 낮은 드립 감량을 나타내었다. 기능성 didpeptide 함량은 IMF에 따라 유의적 차이가 없었으나, High IMF 그룹은 다른 그룹보다 낮은 inosine monophosphate, 높은 hypoxanthine, 낮은 histidine 함량은 나타내었다. 불포화지방산의 비율은 IMF에 따라 유의적 차이가 없었다. 저지방육의 건강지향적 가치를 고려할 때 지나친 IMF를 목표로 하는 육종 및 사양은 지양되어야 할 것으로 판단되었다.

• Food Science of Animal Resources
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• v.32 no.1
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• pp.45-48
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• 2012

The imidazole dipeptide carnosine and its methylated anserine analogues are the major histidine containing dipeptides in vertebrate tissue, especially in skeletal muscle, the heart, and the central nervous system. In this study, the carnosine and anserine content in chicken from different parts and of differing ages was determined and their physiological activities were compared. Anserine was more dominant than carnosine in these tissues and both of them significantly decreased with aging in all parts of chicken muscles. Chicken breast muscle showed the highest content of carnosine and anserine than drumstick and wing. Advanced glycated end-product (AGE) formation was inhibited up to 60% by the extract from 20 wk chicken breast and decreased with aging (90 wk). Anti-oxidation activity was also significantly reduced from 61.2% to 52.9% with aging. As results, anti-glycation and anti-oxidation activity of carnosine and anserine extract from chicken muscle increased proportionally to the amount of those peptides in the muscle, while these decreased with the aging process.