• Korean Chemical Engineering Research
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• 제62권2호
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• pp.173-180
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• 2024

Under ordinary atmospheric circumstances, the gravimetric technique was used to measure the solubility of L-cysteine (L-Cys) and L-alanine (L-Ala) in various solvents, including methyl alcohol, ethyl acetate, and mixtures of the two, in the range o 283.15 K to 323.15 K. Both individual solvents and their combinations showed a rise in the solubility of L-Cys and L-Ala with increasing temperature, according to the analyzed data but when analyzed at a constant temperature in the selected mixed solvents, the solubility declined with decreasing of initial mole fractions of methyl alcohol. To further assess, the relative utility of the four solubility models, we fitted the solubility data using the Jouyban-Acree (J-A), van't Hoff-Jouyban-Acree (V-J-A), Apelblat-Jouyban-Acree (A-J-A), and Ma models followed by evaluation of the values of the RAD information criteria and the RMSD were. The dissolution was also found to be an entropy-driven spontaneous mixing process in the solvents since the thermodynamic parameters of the solvents were determined using the van't Hoff model. In order to support the industrial crystallization of L-cysteine and L-alanine and contribute to future theoretical research, we have determined the experimental solubility, correlation equations, and thermodynamic parameters of the selected amino acids during the dissolution process.

• 한국식품저장유통학회지
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• 제13권4호
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• pp.450-456
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• 2006

쌀을 주재료로 한 쌀 식빵의 제빵 적성을 향상시키고자 제빵 과정 중에 ascorbic acid와cysteine을 첨가하여 식빵의 품질특성을 조사하였다. 쌀 식빵의 RB-3의 경우, 부피는 2,467 mL/kg, 쌀 식빵의 비용적은 5.21 mL/g 그리고 제빵수율 148%로 나타나 상대적으로 다른 배합비로 제조한 식빵에 비해 큰 체적 및 제빵 수율을 나타냈다. 쌀 식빵 crust의 명도 L값은 쌀가루 함량이 높아질수록 높은 값을 나타내었고, crumb 값의 명도 L값도 동일한 결과를 나타냈다. 쌀 식빵의 a와 b값은 각각의 식빵에서 큰 차이가 나타나지 않았다. 쌀 식빵의 경도는 RB-1, 2, 3이 다른 식빵에 비해 상대적으로 낮았으며, 탄력성은 쌀가루 함량이 높을 수록 높게 나타났으며, 씹힘성은 쌀가루 함량이 높을수록 낮게 나타났다. 그리고 응집성은 쌀 식빵 조성에 무관하게 일정한 경향을 나타내지 않았다. 쌀가루 함량이 증가할수록 노화도는 빨리 증가한다는 것과 ascorbic acid 또는 cysteine이 무첨가된 식빵의 노화도가 높게 나타났지만 ascorbic acid과 cysteine이 첨가된 쌀 식빵 RB-3에서 노화도의 정도가 가장 낮게 나타났다. 관능검사 결과, 전체적인 기호도는 쌀 고유의 향과 부드러운 조직감을 갖는 RB-3의 선호도가 가장 높았다.

• 한국의류산업학회지
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• 제16권2호
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• pp.333-338
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• 2014

This study identifies the effects of sodium sulfate and surfactants in the papain treatment of wool fabrics using L-cysteine and EDTA as activators. The research method involves the use of 2% L-cysteine and 7% EDTA as activators at optimal conditions, papain treatment of wool fabrics with the joint use of sodium sulfates and surfactants, and measurements of the weight loss rate, tensile strength, and whiteness. Results showed that for both 2% L-cysteine and 7% EDTA, the maximum papain activity appeared at 0.5% sodium sulfate concentration. In both cases, the papain activity was enhanced at sodium sulfate concentrations lower than 0.5%. In contrast, the papain activity declined at sodium sulfate concentrations higher than 0.5%. The joint use of EDTA with 0.5% sodium sulfate was proven to be very effective in improving the papain activity. The joint use of 2% L-cysteine with 0.5% sodium sulfate appeared slightly effective in improving the activity but resulted in excessive decrease in the tensile strength and whiteness, compared to improvement in the activity. The joint use of surfactants, in the case of L-cysteine, interrupted the papain activity and decreased the tensile strength regardless of the surfactant type and concentration. In the case of EDTA, however, the joint use with 0.1-5% non-ionic surfactants, 0.1-0.5% anionic surfactants, and 0.1% cationic surfactant appeared to improve the papain activity. The maximum papain activity was observed when 0.1% of surfactant was used, regardless of the surfactant type. The nonionic surfactant was the most effective in improving the papain activity.

• Journal of Life Science
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• 제11권2호
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• pp.99-102
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• 2001

Mouse malignant T-lymphoma CS21 cells can grow when cocultured with CAl2 lymph node stromal cells, but they undergo apoptotic cell death with DNA fragmentation when separated from CA12 stromal cells. In the course of examining the effects of the soluble factor (s) secreted by CAl2 stromal cells on CS2l cell growth, we found that thiols including cysteine promoted CS2l cell growth. P388 cell growth was also promoted by various thiols. These results suggest that thiols including cysteine participate in CA12 and P388 cell growth.

• 분석과학
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• 제18권5호
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• pp.396-402
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• 2005

수소화물 발생법-원자흡수 분광계를 이용한 무기비소의 분석 시 예비환원제로써 L-Cysteine, KI, $FeSO_4$의 최적 조건을 찾고자 하였으며, 이들이 분석에 미치는 영향을 서로 비교 연구하였다. 이와 더불어 $H_2SO_4$-trap에 의하여 시료 중 공존 가능성이 있는 유기비소인 MMA(monomethylarsonate)와 DMA(dimethylarsinate)를 제거하여 무기비소만을 분리 분석하였다. 1.8 M 염산과 0.08 M 질산의 혼합산에서 비소 표준용액 20 ppb는 산을 넣지 않았을 때보다도, 높은 흡광도를 나타내었다. L-Cysteine의 경우 0.5 g 정도를 취하고 약 0.07 M의 질산이나 염산의 약 산성 조건에서 30 분 이상을 반응시켰을 경우에 완전히 As(V)는 As(III)로 환원되었다. KI의 경우, 3 g 정도를 취하고 약 0.8 M의 질산 조건에서 1시간 이상 반응시켰을 경우에 완전히 As(V)는 As(III)로 환원되었다. $FeSO_4$의 경우에는, 다른 예비환원제와 비교하여 NaBH4와 $Fe^{2+}$의 반응으로 인한 침전물의 생성으로 튜브내부가 막히게 되어, As(V)가 As(III)로 환원되는 효율의 재현성이 없었다. 분석결과의 정확도를 확인하기 위하여, NIST SRM 1643C Trace Elements in Water ($82.1{\pm}1.2ng/mL$)를 사용하였으며 그 결과는 KI를 예비환원제로 사용하였을 경우에는 97.5%의 회수율이고 L-Cysteine를 예비환원제로 사용하였을 경우에는 101.9%의 회수율로서 두 경우 모두 만족할 만한 수준이였다.

• 전기화학회지
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• 제2권1호
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• pp.27-30
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• 1999

Self-Assembled monolayers of carboxyl-terminated alkanethiols, which is negatively charged in pH 7.0, were usually used to facilitate the electron transfer between the positively charged protein and the electrode. In case of L-cysteine, as it has both positive and negative group, it can be a candidate for a new modifier to facilitate positively charged protein or negatively charged protein. Our investigation of L-cysteine shows that the electron transfer occurs successfully to both cytochrome c (cyt. c) and pyrroloquinoline quinone (PQQ). By using 1-ethyl-3-(3-dime-thlyaminopropyl) carbodiimide (EDC), we made a covalent bond between cyt. c and monolayer. Then PQQ was electrostatically adsorbed to the same monolayer. Cyclic voltammograms show that both molecules do not interfere each other and electron transfer is appreciable.

• Journal of Ecology and Environment
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• 제37권1호
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• pp.31-34
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• 2014

The effectiveness of N-acetyl-L-cysteine (NAC) to protect blood cells against Mitomycin C (MMC) induced genotoxicity was investigated in human chronic myeloid leukemia cells (KCL22) using the alkaline comet assay. The comet assay was selected as sensitive and rapid method for analysis of DNA damage and repair in individual cells. NAC treatment alone did not produce any damage in KCL22 cell. But NAC was found to be effective in reducing genotoxic damage in KCL22 cells exposed to MMC. These results confirm the literature data that, given the safety and ability to reduce DNA damage. NAC may be useful to prevent drug-mediated genotoxicity.

• Applied Biological Chemistry
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• 제30권1호
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• pp.17-23
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• 1987

본 연구는 농축대두단백으로 만든 두유에 L-methionine을 여러가지 농도로 첨가하여 6종의 유산균 (Lactobacillus 4종, Leuconostoc 1종, Streptococcus 1종)의 생육과 산생성에 미치는 영향을 조사하고 아울러 DL-methionine, D-methionine 또는 L-cysteine이 L. acidophilus에 미치는 영향을 조사한 것으로서 그 결과를 요약하면 다음과 같다. 두유에 첨가된 L-methionine은 6종의 유산균 가운데 4종 (L. bulgaricus, L. casei, Leuconostoc mesenteroides, S. lactis)의 생육과 산생성에 거의 영향을 미치지 않았으나 L. acidophilus 2종의 산생성을 억제시켰으며, 같은 L. acidophilus 중에서도 KFCC 12731은 AKU 1122보다 더 큰 영향을 받는 것으로 나타났다. 두유에 첨가된 DL-methionine은 L-methionine과 동일하게 L. acidophilus(KFCC 12731)의 산생성을 현저하게 억제시켰으나, D-methionine은 높은 농도에서도 생육과 산생성에 전혀 영향을 미치지 않았다. 한편 L-cysteine에 의하여 L. acidophilus (KFCC 12731)의 산생성이 다소 억제되었으나 그 정도는 L-methionine이 비하여 매우 완만한 것이었다.

• Preventive Nutrition and Food Science
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• 제22권1호
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• pp.37-44
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• 2017

Sulfur-containing amino acids play important roles in good flavor generation in Maillard reaction of non-enzymatic browning, so aqueous model systems of glucosamine and cysteine were studied to investigate the effects of reaction temperature, initial pH, reaction time, and concentration ratio of glucosamine and cysteine. Response surface methodology was applied to optimize the independent reaction parameters of cysteine and glucosamine in Maillard reaction. Box-Behnken factorial design was used with 30 runs of 16 factorial levels, 8 axial levels and 6 central levels. The degree of Maillard reaction was determined by reading absorption at 425 nm in a spectrophotometer and Hunter's L, a, and b values. ${\Delta}E$ was consequently set as the fifth response factor. In the statistical analyses, determination coefficients ($R^2$) for their absorbance, Hunter's L, a, b values, and ${\Delta}E$ were 0.94, 0.79, 0.73, 0.96, and 0.79, respectively, showing that the absorbance and Hunter's b value were good dependent variables for this model system. The optimum processing parameters were determined to yield glucosamine-cysteine Maillard reaction product with higher absorbance and higher colour change. The optimum estimated absorbance was achieved at the condition of initial pH 8.0, $111^{\circ}C$ reaction temperature, 2.47 h reaction time, and 1.30 concentration ratio. The optimum condition for colour change measured by Hunter's b value was 2.41 h reaction time, $114^{\circ}C$ reaction temperature, initial pH 8.3, and 1.26 concentration ratio. These results can provide the basic information for Maillard reaction of aqueous model system between glucosamine and cysteine.

• Bulletin of the Korean Chemical Society
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• 제23권3호
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• pp.500-502
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• 2002