• Journal of Microbiology and Biotechnology
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• v.18 no.1
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• pp.59-62
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• 2008

The peptide methionine sulfoxide reductases (Msrs) are enzymes that catalyze the reduction of methionine sulfoxide back to methionine. Because of two enantiomers of methionine sulfoxide (S and R forms), this reduction reaction is carried out by two structurally unrelated classes of enzymes, MsrA (E.C. 1.8.4.11) and MsrB (E.C. 1.8.4.12). Whereas MsrA has been well characterized structurally and functionally, little information on MsrB is available. The recombinant MsrB from Bacillus subtilis has been purified and crystallized by the hanging-drop vapor-diffusion method, and the functional and structural features of MsrB have been elucidated. The crystals belong to the trigonal space group P3, with unit-cell parameters a=b=136.096, $c=61.918{\AA}$, and diffracted to $2.5{\AA}$ resolution using a synchrotron-radiation source at Pohang Light Source. The asymmetric unit contains six subunits of MsrB with a crystal volume per protein mass $(V_M)\;of\;3.37{\AA}^3\;Da^{-1}$ and a solvent content of 63.5%.

• Food Science and Biotechnology
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• v.16 no.1
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• pp.1-7
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• 2007

Garlic (Allium sativum L.) contains a specific sulfur compound, the S-allyl derivative of L-cysteine sulfoxide, and has long been known for its antimicrobial activity against various microorganisms, including bacteria, fungi, and protozoa. The principal antimicrobial compound of garlic is S-allyl-L-propenethiosulfinate (allicin) which is generated by an enzyme, alliinase (L-cysteine sulfoxide lyase), from S-allyl-L-cysteine sulfoxide (alliin). This compound exists exclusively in Allium as a major non-protein sulfur-containing amino acid. S-Allyl-L-propenethiosulfinate belongs to the chemical group of thiosulfinates and is a highly potent antimicrobial. The potency of garlic extract is reduced during storage since thiosulfinates are unstable and are degraded to other compounds some of which do not have antimicrobial activity. Diallyl polysulfides and ajoene are sulfur compounds derived from allicin that do possess antimicrobial activity. It was recently found that garlic becomes antimicrobial on heating at cooking temperatures, and that the compound responsible for this is allyl alcohol, which is generated from alliin by thermal degradation.

• Journal of Nutrition and Health
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• v.13 no.3
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• pp.150-154
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• 1980

For the purpose of clarifying the changes of free amino acid content in seeds of Korean mung bean during the ripening process, samples ranging in five stages-10, 15, 20, 25 and 30 days after blooming were collected. The results obtained were as follows: 1) Amino acids detected in the first stage were lysine, histidine, arginine, cystine, aspartic acid, threonine (including serine), glutamic acid, valine, methionine sulfoxide and methionine sulfone. 2) In the second stage (15 days after blooming) more amino acids such as glycine, isoleucine, tyrosine, phenylalaninc, and methionine were detected in addition to those in the first stage. More methionine was appeared, while the level of methionine sulfoxide and methionine sulfone was decreased. 3) In the 3rd stage leucine was first detected. The level of leucine was increased slowly as the seed was being ripened. After 4th stage methionine sulfoxide and methionine sulfone were not detected, while the level of methioniene was steadily increased. 4) After 20 days the levels of lecuine, valine. isoleucine, and methionine were increased, while the others were either decreased or remained at the same level.

• Journal of Life Science
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• v.19 no.3
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• pp.343-348
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• 2009

Magnaporthe oryzae, a major cause of rice blast, is one of the most destructive plant fungal pathogens. Secretion of reactive oxygen species (ROS) during the infection phase of plant pathogenic fungus plays a key role in the defense mechanism of a plant. ROS causes oxidative damage and functional modification to the proteins in a pathogenic fungus. Methionine, especially, is a major target of ROS, which oxidizes it to methionine sulfoxide. To survive from the attack of ROS, plant pathogenic fungus has antioxidative systems - one example would be methionine sulfoxide reductase B (MSRB), which reverses the oxidative alteration of methionine to methionine sulfoxide. In the present study, identification and molecular characterization of the MSRB gene in M. oryzae KJ201 were investigated. The MSRB gene was amplified by PCR from the M. oryzae KJ201 genomic DNA. The copy number of MSRB in the genome of M. oryzae KJ201 was identified by Southern blot analysis, which revealed that the gene exists as a single copy. To study the molecular function of an MSRB gene, the expression level of the MSRB gene was assayed with hydrogen peroxide treatment by Northern blot analysis and RT-PCR. The expression of the MSRB gene was increased by treatment of hydrogen peroxide, without significant correlation to hydrogen peroxide concentrations. These results indicate that the MSRB gene in M. oryzae KJ201 could contribute to protection against plant defense compounds such as ROS and offer a novel strategy for the control of rice blast.

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.319-320
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• 2011

• BMB Reports
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• v.44 no.10
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• pp.669-673
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• 2011

Human methionine sulfoxide reductase B3A (hMsrB3A) is an endoplasmic reticulum (ER) reductase that catalyzes the stereospecific reduction of methionine-R-sulfoxide to methionine in proteins. In this work, we identified an antimicrobial peptide from hMsrB3A protein. The N-terminal ER-targeting signal peptide (amino acids 1-31) conferred an antimicrobial effect in Escherichia coli cells. Sequence and structural analyses showed that the overall positively charged ER signal peptide had an Argand Pro-rich region and a potential hydrophobic ${\alpha}$-helical segment that contains 4 cysteine residues. The potential ${\alpha}$-helical region was essential for the antimicrobial activity within E. coli cells. A synthetic peptide, comprised of 2-26 amino acids of the signal peptide, was effective at killing Gram-negative E. coli, Klebsiella pneumoniae, and Salmonella paratyphi, but had no bactericidal activity against Gram-positive Staphylococcus aureus.

• BMB Reports
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• v.44 no.12
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• pp.805-810
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• 2011

Methionine sulfoxide reductase A (MSRA) is a ubiquitous enzyme that has been demonstrated to reduce the S enantiomer of methionine sulfoxide (MetSO) to methionine (Met) and can protect cells against oxidative damage. In this study, we isolated a novel MSRA (SlMSRA2) from Micro-Tom (Solanum lycopersicum L. cv. Micro-Tom) and characterized it by subcloning the coding sequence into a pET expression system. Purified recombinant protein was assayed by HPLC after expression and refolding. This analysis revealed the absolute specificity for methionine-S-sulfoxide and the enzyme was able to convert both free and protein-bound MetSO to Met in the presence of DTT. In addition, the optimal pH, appropriate temperature, and $K_m$ and $K_{cat}$ values for MSRA2 were observed as 8.5, $25^{\circ}C$, $352{\pm}25\;{\mu}M$, and $0.066{\pm}0.009\;S^{-1}$, respectively. Disk inhibition and growth rate assays indicated that SlMSRA2 may play an essential function in protecting E. coli against oxidative damage.

• Journal of the Korean Chemical Society
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• v.31 no.2
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• pp.197-202
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• 1987

Sigmatropic rearrangement of cis and trans-2-methyl-N-phenyl-1,3-oxathiolane-2-acetamide (b) and (c) gave unisolable sulfenic acids (d) and (f), respectively. These sulfenic acids were confirmed by deuterium exchange reactions involving 2-methylene and 2-methyl groups. The reactions also showed that no isomerization between the cis and trans sulfoxides (b) and (c) occurred under neutral conditions. However, the isomerization took place in the presence of acid catalyst. Stereospecific recyclization of sulfenic acids to the sulfoxides is attributable to possible hydrogen bonding between sulfenyl oxygen and NH proton or it arises from the geometrical requirements of the reacting bond and atoms in the reverse sigmatropic rearrangement. In the oxidation of 1, 3-oxathiolane, cis sulfoxide (b) could be obtained selectively in high yield by using $H_2O_2$-benzene seleninic acid.

• Food preservation and processing industry
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• v.7 no.1
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• pp.33-44
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• 2008

마늘의 저장 중 생리활성과 향미에 중요한 영향을 미치는 성분의 변화를 발표된 논문을 중심으로 정리하여 살펴보았다. 또한 마늘의 냄새를 최소화하고 생리활성을 극대화할 수 있는 기능성식품의 소재개발 타당성을 살펴보기 위하여 열처리(blanching)로 마늘 중의 효소를 모두 불활성화 시킨 후, 이에 마늘로부터 추출한 alliinase를 가하여 반응조건에 따른 alk(en)yl thiosulfinates 생성 및 이들의 분해산물인 휘발성 황함유화합물의 함량변화를 측정하였다. 수확한 마늘의 최종 저장물질로 알려진 -glutamyl-S-alk(en)yl-L-cysteines는 마늘중에 존재하는 -glutamyl-transpeptidase 및 oxidase의 작용에 의하여 감소한 반면 S-alk(en)yl cysteine sulfoxide는 감소한 만큼 증가하였으며, 이는 $-3^{\circ}C$ 및 실온($23^{\circ}C$)에서 보다도 냉장온도($4^{\circ}C$)에서 가장 많이 변화하는 것으로 나타났다. 이러한 감소 및 증가현상은 -glutamyl-S-(2-popenyl)-L-cysteine이 -glutamyl-S-(trans-1-propenyl)-L- cysteine이나 -glutamyl-S-methyl-L-cysteine보다 더 컸다. -glutamyl-S-(2-propen yl)-L-cysteine은 $4^{\circ}C$에서 저장 60일 만에 66%가 감소한 반면 이로부터 생성된 S-(2- popenyl)-L-cysteine sulfoxide는 그 만큼 증가하였다. -glutamyl-S-(trans-1-propenyl)-L-cysteine 및 -glutamyl-S-methyl-L-cysteine도 $4^{\circ}C$에서 150일간 저장한 경우 각각 81% 및 39%가 감소하고, 이들로부터 각각 생성된 S-(trans-1- propenyl)-L-cysteine sulfoxides 및 S-methyl-L-cysteine sulfoxide는 증가하였다. 한편 열처리 마늘에 alliinase를 가하여 함황화합물을 재생성 시킨 결과 8종의 S-alk(en)yl cysteine sulfoxides를 확인할 수 있었다. S-(2-propenyl)-L-cysteine sulfoxide은 전체 thiosulfinates함량의 약 60%를 차지하는 것으로 나타났다. 100, 200, 300 및 400 unit의 alliinase를 첨가하여 15분간 반응시킨 결과 총 thiosulfinates는 생마늘(대조구)에 비하여 각각 37, 68, 77 및 80%가 생성되는 것으로 나타났다. GC/MSD를 이용하여 대조구 및 효소를 첨가하여 반응시킨 시료의 휘발성 향기성분을 분석한 결과 alliinase를 100, 200, 300 및 400 unit 첨가하여 15분간 반응시키면 각각 마늘의 휘발성 향기성분이 25, 36, 66및 76% 씩 재 생성되는 것으로 나타났다. 이상의 결과를 종합해 볼 때 마늘을 이용한 제품개발이나 연구를 할 경우 마늘의 저장조건에 따른 생리활성물질의 분석결과를 근거로 하여 이루어져야 하며, 또한 효소를 이용하여 적절히 반응시키면 마늘 냄새를 $30{\sim}80%$ 범위 내에서 조절이 가능한 것으로 나타났다.

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.2
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• pp.157-163
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• 2001

The effects of dimethyl sulfoxide (DMSO) were studied in two groups of Xenopus oocytes, one expressing ATP sensitive $K^+\;(K_{ATP})$ channel comprised of sulfonylurea receptor SUR1 and inwardly rectifying $K^+$ channel subunit Kir6.2, and the other expressing renal $K_{ATP}$ channel ROMK2. At concentrations of $0.3{\sim}10%$ (vol/vol) DMSO inhibited whole cell Kir6.2/SUR1 currents elicited by bath application of sodium azide (3 mM) in a concentration-dependent manner. The inhibition constant and Hill coefficient were 2.93% and 1.62, respectively. ROMK2 currents, however, was not affected significantly by DMSO. The results support the idea that DMSO inhibits $K_{ATP}$ channel expressed in Xenopus oocyte through a protein-specific mechanism(s) that remains to be further elucidated.