• Bulletin of the Korean Chemical Society
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• v.7 no.1
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• pp.25-29
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• 1986

The reaction of cysteine with cinnamaldehyde have been studied kinetically and thermodynamically. It was found that the reaction proceeds in two steps; formation of the monoadduct by a Michael type addition followed by the nucleophilic attack of the second cysteine to the carbonyl carbon of the monoadduct to afford the thiazolidine derivative. A reaction profile for the reaction of cysteine with cinnamaldehyde was constructed based on the thermodynamic parameters analyzed for the forward and the reverse reactions. It was assumed that the second step of this reaction accompanies an intermediate, a Schiff base.

• Applied Biological Chemistry
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• v.33 no.2
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• pp.109-115
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• 1990

This study was carried out to investigate the effect of L-cysteine and sodium sulfite on heat inactivation of soybean trypsin inhibitor(STI) and to determine cultivar difference in the inhibitory activity of STI. Effect of L-cysteine and sodium sulfite at different concentrations, pH's, and lengths of treatment on inactivation of STI were studied. The inactivation of STI was spectrophotometrically determined by measuring the rate of production of p-nitroaniline from synthetic substrate, N-benzoyl-DL-arginine-p-nitroanilide. Addition of L-cysteine and sodium sulfite increased magnitude of heat inactivation and greatly inhibited the re-activation of STI. There was no difference STI inactivation in among soybean cultivars employed. The trypsin inhibitory activity of STI of the soybean cultivars ranged from 64.7 to 86.4 TIU(trypsin inhibitor unit) per gram soyflour and the decreasing order of the TIU was Jangback>Hill>Jangyeab, Kwangkyo> Danyeab>Dangkyung>Paldal, Saeal, Duckyu>Hwangkeum. Inhibitory activity of STI was correlated with cysteine $content(r=0.6568^*)$ and with $digestivility(r=-0.7695^{**})$, but there was no correlation between the protein content and the inhibitory activity of STI.

• Mass Spectrometry Letters
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• v.3 no.1
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• pp.10-14
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• 2012

Artificially oxidized cysteine residues in peroxiredoxin 6 (Prx6) were detected by electrospray interface capillary liquid chromatography-linear ion trap mass spectrometry after the preparation of two-dimensional gel electrophoresis (2D-GE). We used Prx6 as a model protein because it possesses only two cysteine residues at the 47th and 91st positions. The spot of Prx6 on 2D-GE undergoes a basic (isoelectric point, pI 6.6) to acidic (pI 6.2) shift by exposure to peroxide due to selective overoxidation of the active-site cysteine Cys-47 but not of Cys-91. However, we detected a tryptic peptide containing cysteine sulfonic acid at the 47th position from the basic spot and a peptide containing both oxidized Cys-47 and oxidized Cys-91 from the acidic spot of Prx6 after the separation by 2D-GE. We prepared two types of oxidized Prx6s: carrying oxidized Cys-47 (single oxidized Prx6), and other carrying both oxidized Cys-47 and Cys-91 (double oxidized Prx6). Using these oxidized Prx6s, the single oxidized Prx6 and double oxidized Prx6 migrated to pIs at 6.2 and 5.9, respectively. These results suggest that oxidized Cys-47 from the basic spot and oxidized Cys-91 from the acidic spot are generated by artificial oxidation during sample handling processes after isoelectric focusing of 2D-GE. Therefore, it is important to make sure of the origin of cysteine oxidation, if it is physiological or artificial, when an oxidized cysteine residue(s) is identified.

• Parasites, Hosts and Diseases
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• v.32 no.4
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• pp.231-242
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• 1994

Pnragonimus westermnni, the lung fluke, is known to migrate to the pulmonary tissue of mammalian hosts and causes pathological changes in the lungs. An acidic thiol-dependent proteinase with a molecular weight of approximately 20,000 daltons was purified to homogeneity using ion-exchange chromatography and gel filtration chromatography. On SDS-PAGE, the molecular weight of the enzyme was 17,500 daltons. Isoelectric point was 6.45. The enzyme was similar to the acidic cysteine proteinase of vertebrates in the properties of pH optimum, substrate specificity and inhibitor sensitivity. Enzymatic activity was stable at pH 5.5 for at least two days when stored at 4℃. The cysteine proteinase was capable of degrading collagen and hemoglobin. Sera of patients with paragonimiasis and mice infected with R westermani reacted in immunoblots with the partially purified proteinase. This result suggested that the cysteine proteinase of P. westermnni may play a role in migration in tissues, and in acquisition of nutrients by parasites from the host. It is also potentially an antigen for the serodiagnosis of paragonimiasis.

• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1045-1052
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• 2003

To develop a burnt beef flavor by reaction flavor technology, hydrolyzed vegetable protein (HVP) was reacted with precursors. Ribose, cysteine, furaneol, thiamin, methionine, garlic powder, and phospholipid were selected as suitable precursors for producing a burnt beef flavor. HVP and the selected precursors were reacted in a high pressure reactor to optimize reaction parameters, such as temperature, time, and water content. Optimum reaction conditions were $130^{\circ}C$, 1 hr, and 7.5% water addition. A burnt beef flavor was generated without pH adjustment. On the basis of an omission test, cysteine, furaneol, thiamin, and garlic powder were evaluated for optimization using response surface methodology. The optimum composition of precursore was determined to be 7.7% cysteine, 7.3% furaneol, 2.1% thiamin, and 6.9% garlic powder. Based on these results, optimum reaction conditions for the production of a burnt beef flavor from HVP were 5% ribose, 5% methionine, 5% phospholipid, 7.7% cysteine, 7.3% furaneol, 2.1% thiamin, 6.9% garlic powder, 7.5% water addition, $130^{\circ}C$ reaction temperature, and 1hr reaction time.

• Journal of Pharmaceutical Investigation
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• v.11 no.1
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• pp.1-5
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• 1981

Through hydrolysis of hydantoin with barium hydroxide amino acid can be prepared. By applying this method new four ${\alpha}-phenyl-cysteine$ derivatives were synthesized.

• Journal of Microbiology
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• v.35 no.2
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• pp.97-102
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• 1997

Cysteine desulfhydrase (EC 4.4.1.1.) was purified from the culture supernatant of Streptomyces albidoflavus SMF301 by hydroxyapatite, gel filtration and Resource Q ion-exchange chromatography with a purification fold of six identical subunits. The enzyme was stabilized by dithiothreitol and pyridoxal 5'-phosphate during the purification procedures. The optimum pH and temperature were pH 8.6 and 35$^{\circ}C$, respectively. The N-terminal amino acid sequence was identified as A-P-L-P-T-A-D-V-R-S-D-P-G-Y-R-E-W-L-G-E-A-V. The purified cystein desulfhydrase had a high substrate specificity toward cysteine, and exhibited no cystahionine $\gamma$-lyase activity. The $K_m$ value for cysteine was determined to be 0.37 mM.

• Journal of Dairy Science and Biotechnology
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• v.23 no.2
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• pp.107-114
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• 2005

The trend towards ageing populations has been observed over many years in Europe and the US but has accelerated significantly in developed countries in Asia including Japan and South Korea. In the latter country the elderly population (65+) has increased 5-fold between 1960 and 2000 and this group will comprise 40% of the population by 2050. This creates a new socio-economic group with specific demands and considerable spending power. As ageing occurs a range of changes occur in the body that can be moderated by adjustments in nutrition. A significant body of evidence points to changes in the balance of glutathione synthesis and utilisation as people age. Glutathione is tile most important natural anti-oxidant of the body and the amounts present can become limited by available cysteine in the diet. A cysteine-enriched peptide product, Cysteine Peption$^{TM}$ has been developed by DMV International for dietary supplement and food applications. A qualitative consumer trial has indicated benefits including improved sleep and more energy. Animal and clinical trial will be described that provide indications on bioavailability and possible mechanisms of action of Cysteine Peption$^{TM}$ with particular focus on the ageing population.

• Toxicological Research
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• v.22 no.1
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• pp.39-45
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• 2006

As the antioxidant and free radical scavenger, glutathione (GSH) participates in the preservation of cellular redox status and defense against reactive oxygen species and xenobiotics. Glutamate-cysteine ligase (GCL; also known as ${\gamma}$-glutamylcysteine synthetase, EC 6.3.2.2) is the rate limiting enzyme in GSH synthesis. In the present study, the accurate method for determination of GCL activity in crude liver extracts was developed by measuring both ${\gamma}$-glutamylcysteine and GSH from cysteine in the presence of glutamate, glycine and an ATP-generating system. We added glycine to promote the conversion of ${\gamma}$-glutamylcysteine to GSH, and to minimize the possibility of ${\gamma}$-glutamylcysteine metabolism to cysteine and oxoproline by ${\gamma}$-glutamylcyclotransferase. We established optimal conditions and substrate concentrations for the enzyme assay, and verified that inhibition of GCL by GSH did not interfere with this assay. Therefore, this assay of hepatic GCL under optimal conditions could provide a more accurate measurement of this enzyme activity in the crude liver extracts.

• YAKHAK HOEJI
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• v.47 no.4
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• pp.218-223
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• 2003

Effect of taurine treatment on metabolism of glutathione (GSH) was studied in adult male ICR mice. An acute injection of taurine (250 mg/kg, ip) resulted in a significant decline of hepatic GSH level at t = 6 hr, but plasma GSH level was not altered. The activity of GSH-related enzyme in liver, such as GSH peroxidase, GSSG reductase, GSH S-transferases, ${\gamma}$-glutamylcysteine synthetase or ${\gamma}$-glutamyltranspeptidase, was not affected by taurine at t = 2.5 or 6 hr. Plasma cysteine and cystine levels were elevated rapidly following taurine treatment. Hepatic cysteine level was decreased by taurine, reaching a level approximately 70％ of control at t = 4 and 6 hr. In conclusion, the results indicate that an acute dose of taurine decreases hepatic GSH level by reducing the availability of cysteine, an essential substrate for synthesis of this tripeptide in liver. It is also suggested that taurine may decrease the cysteine uptake by competing with this S-amino acid for a non-specific amino acid transporter.