• Bulletin of the Korean Chemical Society
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• 제35권4호
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• pp.1159-1164
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• 2014

A simple, highly sensitive and selective method based on the rhodamine B-covered gold nanoparticle with dual-readout (colorimetric and fluorometric) detection for $\small{L}$-cysteine is proposed. A mechanism is that citrate-stabilized AuNPs were modified with RB by electrostatic interaction, which enables the nanometal surface energy transfer (NSET) from the RB to the AuNPs, quenching the fluorescence. In the presence of $\small{L}$-cysteine, it was used as a competitor in the NSET by the strongly Au-S bonding to release RB from the Au surface and recover the fluorescence, and the red-to-purple color change quickly, which was monitored simply by the naked eye. Under the optimum conditions, the detection limit is as low as 10 nM. The method possessed the advantages of simplicity, rapidity and sensitivity at the same time. The method was also successfully applied to the determination of $\small{L}$-cysteine in human urine samples, and the results were satisfying.

• Food Science and Biotechnology
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• 제16권3호
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• pp.343-348
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• 2007

Starch contents play important roles in determining the fruit quality. Stawberry accumulates starch in the early stages and then mobilized into soluble sugars during fruit ripening. To date the molecular studies on the ADP-glucose pyrophosphorylase (AGPase), a key enzyme of starch biosynthesis, were not reported. cDNAs encoding small (FagpS) and large (FagpL1 and FaspL2) AGPase subunits were isolated from strawberry (Fragaria ${\times}$ ananassa Duch. cv. Niyobou). Both FagpS and FagpL1 cDNAs have open reading frames deriving 55-58 kDa polypeptides, where FagpL2 contains a partial fragment. Sequence analyses showed that FagpS has a glutamate-threonine-cysteine-leucine (ETCL) instead of a glutamine-threonine-cysteine-leucine (QTCL) motif found in all the dicot plants except for Citrus. In fruits, FagpS and FagpL1 were expressed in all stages with a little change in the amounts of transcripts. In the case of FagpL2, we were not able to detect any signal from all stages of fruit development and all tissues except for very a weak signal from the leaf. The results indicate that FagpL1 and FagpL2 show ubiquitous and leaf-specific expression patterns, respectively. The studies suggest that the starch contents in strawberry might be controlled by the expression of AGPase gene at both the transcriptional and post-transcriptional levels during fruit development.

• BMB Reports
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• 제39권3호
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• pp.278-283
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• 2006

Defensins are small cysteine rich peptides with a molecular mass of 5-10 kDa and some of them exhibit potent antifungal activity. We have cloned the coding region of a cDNA of 225 bp cysteine rich defensin, named as Tfgd1, from the legume Trigonella foenum-graecum. The amino acid sequence deduced from the coding region comprised 74 amino acids, of which the N-terminal 27 amino acids constituted the signal peptide and the mature peptide comprised 47 amino acids. The protein is characterized by the presence of eight cysteine resisdues, conserved in the various plant defensins forming four disulphide bridges, which stabilize the mature peptide. The recombinant protein expressed in E coli exhibited antifungal activity against the broad host range fungus, Rhizoctonia solani and the peanut leaf spot fungus, Phaeoisariopsis personata.

• Bulletin of the Korean Chemical Society
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• 제35권6호
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• pp.1887-1890
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• 2014

• Bulletin of the Korean Chemical Society
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• 제17권5호
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• pp.433-436
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• 1996

Cobalt(Ⅲ) complexes of trifunctional amino acid and N,N'-diethylethylenediamine-N,N'-di-α-butyrate(deedba), s-cis-[Co(deedba)(L-aa)] (L-aa=S-methyl-L-cysteine, L-aspartic acid, L-glutamic acid) have been prepared from the reaction between the s-cis-[Co(deedba)(Cl2)]- complex and the corresponding amino acid. The amino acids have been found to coordinate through the amine and carboxylate groups. The S-methyl-L-cystene is coordinated not by the sulfur donor atom, but by the nitrogen and oxgen donor atoms, and the L-aspartic and L-glutamic acids are coordinated to the cobalt(Ⅲ) ion via formation of the five-membered glycinate chelate ring. Relatively small optical activity shown by the complexes is due to the chiral center present in the amino acids.

• 한국식품영양과학회지
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• 제12권2호
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• pp.176-187
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• 1983

마늘 flavor의 발현과 flavor에 영향을 미치는 요인들에 대하여 살펴보았다. 마늘 flavor는 alk(en)yl-$\small{L}$-cysteine sulfoxide에 alliinase가 작용하여 생성된 alk(en)yl thiosulfinate에 의한 것으로 alk(en)yl기는 주로 allyl기이다. 마늘의 flavor세기는 성숙도 부위, 배양조건, 저장조건, 가공처리법에 따라 달라진다. 마늘의 flavor를 증진시키기 위해서는, 마늘 재배시 토양내 유황의 함량이 많을수록 flavor 전구체의 생성량이 증가하여 flavor 세기가 커졌으므로, 충분한 양의 유황을 공급하되 alliin함량이 최대로 되기 위한 다른 무기질과의 조성비율 중 현재까지 연구된 2종류의 무기질 조성(NS : ${NO_3}^{-2}$, 40%, ${SO_4}^{-2}$, 60%, NP : ${NO_3}^{-2}$, 62%, ${PO_4}^{-3}$, 38%)을 고려하여야 할 것이며, 너무 습하지 않은 토양에서 재배하는것이 바람직하다. 마늘은 성숙함에 따라 인편내 alliin함량도 증가되므로 완전히 성숙한 후에 수확하는 것이 바람직하다. 또한 마늘의 flavor를 유지하기 위해서는 수확후 저장하는 동안에 일어나는 flavor 손실을 최소로 하여야 할 것이다. 자연조건에 저장하는 동안에 일어나는 flavor 손실은 주로 호흡, 발아, 부패에 의한 것이므로 이를 억제하기 위한 저장방법으로 저온 저습저장, 예건처리, gas치환, 발아억제 처리등의 방법이 있으나 현재까지 경제, 실용성등을 고려하여 가장 많이 사용하는 방법은 예건처리후 저온저습조건에 저장하는 방법이다. 가공처리된 마늘은 생마늘에 비하여 flavor가 상당히 많이 감소되는데 건조시켜 분말로 만들 경우, 건조방법에 따라 flavor 감소정도는 크지만 flavor 감소율이 적은 방법 (진공건조, 동결건조)이라도 그 손실률은 거의 50%에 달한다. 그외의 마늘 가공처리품들인 oil이나 extract등도 제조시 기질과 효소가 접촉하는 과정을 거칠 때 flavor의 손실이 크므로 되도록 이면 flavor 손실이 크지 않은 방법으로 제조하는 것이 바람직하다. 마늘 flavor를 합성하는 방법으로는 thiosulfinate 합성에 의한 방법과 alk(en)yl-$\small{L}$-cysteine sulfo-xide-alliinase 분해물에 의한 방법, 그리고 $\small{L}$-5-alk(en)yl thiomethylhydantoin${\pm}$S-oxides에 의한 방법이 있으며 이들 방법에 의해 생마늘과 유사한 flavor를 얻을 수 있어 앞으로 식품첨가물로서 기대되는 바이다.

• Applied Biological Chemistry
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• 제2권
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• pp.36-39
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• 1961

It has been ascertained that S-(1, 2-dichlorovinyl) L-cysteine (DCVC) is probably the toxic component in the trichloro-ethylene extracted soybean oil meal on the bovine. For the study of the metabolites of DCVC, the components with radioactive $S^{35}$-in the urine of the calf, to which $S^{35}$-DCVC was administrated, were separated using of cellulose powder with propanol-water (70:30 V/V) which is easily removable by evaporation. As the results followings were obtained: Peak 1, which shows fractions containing single $S^{35}$-radioactive components, whose Rf is 0.815 Peak 2, which shows fractions containing jingle $S^{35}$-radioactive component, whose Rf is 0.447 Peak 3, which shows fractions containing both $S^{35}$-radioactive components whose Rfs are 0.090 and 0.171 Peak 4, which shows fractions containing single $S^{35}$-radioactive component, whose Rf is 0.142. Peak 5, which shows fractions containing single $S^{35}$-radioactive component, whose Rf is 0.084. Besides these, two of small peak were obtained. Although, the resolving power of the cellulose powder column is not sufficient, it is applicable for the study of the components of metabolytes of DCVC conveniently with the rest of removable solvent easily. Also the components with radioactive $S^{35}$ in the feces of the calf were separated using citrate buffer gradient system of Moore and stein. As the results; three $S^{35}$-radioactive components were separated.

• 대한소아치과학회지
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• 제30권1호
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• pp.33-40
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• 2003

구취를 일으키는 구강 내 혐기성 세균 일종인 Fusobacterium nucleatum은 유황 성분이 함유된 배지에서 $H_2S$와 같은 휘발성 유황화합물을 생성하고 철 성분과 결합하면 FeS를 형성한다. 구강내 여러 인자에 의하여 Fusobacterium nucleatum에 의하여 생성되는 유황화합물 농도가 달라진다. 본 연구에서는 Fusobacterium nucleatum의 유황화합물 생성시 영양 물질과 pH의 영향을 연구하여 다음과 같은 결과를 얻었다. 1. 배지에 sodium thiosulfate가 1.0% 되도록 첨가하면 배지의 흡광도는 $0.817{\pm}0.032$로, L-cysteine hydrochloride를 0.05% 되도록 첨가하면 $1.297{\pm}0.024$가 되었다. 2. 배지에 자일리톨을 첨가하면 배지의 흡광도는 $0.799{\pm}0.032$인데 반하여 포도당과 병합으로 첨가하면 $1.775{\pm}0.003$으로, 과당과 병합으로 첨가하면 $1.648{\pm}0.022$로 증가하였다. 3. 배지의 pH가 5.5 이상이면 휘발성 유황화합물 농도는 20,000 ppb이상이었다. 배지의 흡광도는 배지 내 L-cysteine hydrochloride 농도가 높을수록 높았으며, 배지의 pH가 산성으로 갈수록 낮았다. 4. 배지 위에 증류수나 식염수가 있을 때, 그리고 그 양이 적을수록 휘발성 유황화합물 농도는 높았다. 이상의 결과를 종합하면 Fusobacterium nucleatum에 의한 유황화합물 생성 이 자일리톨과 산에 의하여 억제되었다.

• Journal of Microbiology and Biotechnology
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• 제27권4호
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• pp.747-758
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• 2017

Chronic wounds, pressure sores, lesions, and infections of microbial origin in bedridden, paralyzed, or malnutrition patients remain the object of study of many researchers. A variety of factors behind the development of these disorders are related to the patient's immune system, making it unable to respond effectively to the treatment of the wound. These factors can be properly controlled, giving particular importance to the ethiology and stage of the wound, as well as the time periods corresponding to the replacement of the dressings. The present research reports a novel foam/soft material, ${{\small}L}$-Cys-g-PCL, with an application for decubitus/pressure ulcers, especially for wounds with a difficult healing process due to infections and constant oxidation of the soft tissues. During this work, the interactions between S. aureus and ${{\small}L}$-Cys-g-PCL foam were studied under conditions that simulate decubitus ulcers; namely, pH and exudate. The effects of duration of grafting (1 or 8 h) and pH (7.0 and 8.9) on wettability, surface energy, swelling, and porosity were also evaluated. Results showed an effective microbicidal activity exhibiting an inhibition ratio of 99.73% against S. aureus. This new ${{\small}L}$-Cys-g-PCL soft material showed saftey to contact skin, ability to be shaped to fill in sunken holes (craters) - pressure ulcers stage III - and to act as a smart material responsive to pH, which can be tailored to develop better swelling properties at alkaline pH where exudates are normally higher, so as to address exudate self-cleaning and prevention of desiccation.

• 대한화학회지
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• 제15권5호
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• pp.256-265
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• 1971

An ESR study has been made on free radicals produced in frozen aqueous solutions (ices) of glycine, DL-${\alpha}$-alanine, DL-serine, L-cysteine, DL-leucine and DL-isoleucine by gamma-irradiation at dry ice temperature. All free radicals induced were decayed concomitant to the successive annealing but the radical species which is believed to be dominant seems to be stable even near the melting point of the ice. These dominant species were found to be identical to those resulted from direct action of radiation in the solid at room temperature. Small but significant changes in the spectra of glycine and DL-${\alpha}$-alanine were observed by varying the microwave power. These results seem to support the view that the spectra obtained were composite consisting of more than two different resonances having different power saturation characteristics. The relative contribution of unidentified resonances to the composite spectra was greater for solutions of low concentration. These resonances are assumed to be induced by indirect effects, mainly hydrogen abstraction by radiation produced hydroxyl radicals and also C-N bond cleavage by hydrated electrons.