• BMB Reports
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• 제32권5호
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• pp.480-485
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• 1999

Tyrosine phenol-lyase of thermophilic Symbiobacterium sp. SC-1, which is obligately and symbiotically dependent on thermophilic Bacillus sp. SK-1, was purified and characterized. The enzyme is composed of four identical subunits and contains approximately 1 mol of pyridoxal 5'-phosphate (PLP) per mol subunit as a cofactor. The enzyme showed absorption maxima at 330 and 420 nm, and lost this absorption profile by treatment with phenylhydrazine. The apparent dissociation constsnt, $K'_D$, for PLP was determined with the apoenzyme to be about $1.2\;{\mu}M$. The isoelectric point was 4.9. The optimal temperature and pH for the $\alpha,\beta$-elimination of L-tyrosine were found to be $80^{\circ}C$ and pH 8.0, respectively. The substrate specificity of the enzyme was very broad: L-amino acids including L-tyrosine, 3,4-dihydroxyphenyl-L-alanine (L-DOPA), L-cysteine, L-serine, S-methyl-L-cysteine, $\beta$-chloro-L-alanine, and S-(o-nitrophenyl)-L-cysteine all served as substrates. D-Tyrosine and D-serine were also decomposed into pyruvic acid and ammonia at rates of 7% and 31% relative to their corresponding L-enantiomers, respectively. D-Alanine, which was inert as a substrate in a, $\beta$-elimination, was the only D-amino acid racemized by the enzyme. The $K_m$ values for L-tyrosine, L-DOPA, S-(o-nitrophenyl)-L-cysteine, $\beta$-chloro-L-alanine, and S-methyl-L-cysteine were 0.19, 9.9, 0.36, 12, and 5.5 mM, respectively.

• 대한화학회지
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• 제33권5호
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• pp.504-509
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• 1989

N,N'-dimethylethylenediamine-N,N'-di-${\alpha}$-butyric acid(dmedba)와 세자리 아미노산과의 코발트(III) 착물인 [Co(dmedba)(L-aa)] (L-aa = S-methyl-L-cysteine, L-methionine, L-glutamic acid, L-aspartic acid)는$ s-cis-[Co(dmedba)Cl_2]-^ 착물과 아미노산과의 반응으로부터 얻었다. 아미노산들은 [Co(dmedda)(L-dd)] 착물과 같이 아민과 카르복실그룹을 통하여 배위되었다. 이 착물들의 구조는 ^1H-NMR, IR, UV$ 스펙트럼 데이타와 원소분석으로 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제13권4호
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• pp.483-486
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• 2003

3'-[S-Methyl-cysteinyl]-3'-amino-3'-deoxy-N,N- dimethyl adenosine, cystocin, is a biosynthesized antibiotic material newly identified from Streptomyces sp. GCA0001. Its structure was found to be similar to puromycin, where the terminal tyrosine is replaced by a methyl cysteine. NMR data prove that the 3-ammo ribose is connected to dimethylaminopurine through the anomeric carbon at 1'-carbon. The methyl cysteinyl unit is connected to the amino unit of ribose by peptide bond. The verification of the structure was performed by comparing the puromycin nucleosides resulted from the hydrolysis of cystocin and puromycin, respectively. Antibiotic activity of cystocin against Streptococcus was found to be two times more potent than that of puromycin.

• 생명과학회지
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• 제18권1호
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• pp.9-15
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• 2008

마늘의 주성분인 유황 함유 화합물을 이용하여 사람 low density lipoprotein (LDL)의 산화에 대하여 항산화 활성을 실험하였다. 유황함유화합물인 1-methyl-1-cysteine, dimethyl trisulfide 및 1-vinyl-4H-1,3-dithiin의 농도를 각각 40, 60, $80{\mu}g/ml$ 씩 첨가하여 $Cu^{2+}$ 및 macrophages 유도로 LDL을 산화할 때 항산화 효능을 TBARS로 측정한 결과 용량 의존형으로 나타났으며 유황 함유 화합물이 모두 효능이 있었으며 항산화력은 2-vinyl-4H-1,3-dithiin > 1-methyl-1-cysteine > methyl trisulfide 순이었다. 이 때 유황 함유 화합물의 LDL에 대한 공액 2중결합에 대한 항산화 실험에서도 항산화 효과가 있었으며 $60{\mu}g/ml$의 농도에서 거의 억제되었다. 유황 함유 화합물 중에서는 2-vinyl-4H-1,3-dithiin이 다른 유황 함유 화합물에 비하여 약간 높은 항산화 효능을 나타내었다. Endothelial cell을 이용한 LDL의 산화에 대한 억제율은 2-vinyl-4H-1,3-dithiin이 가장 높게 나타났다.

• Archives of Pharmacal Research
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• 제17권6호
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• pp.428-433
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• 1994

The methabolism and phamacokinetics of a mixed disulfide S-(N, N-diethyldithiocarbamoyl)-N-acetyl-L-cysteine (AC-DDTC) were studied in rats. Two metabolites of AC-DDTC following iv and po administration were indentified in plasma and liver by HPLC and GC, namely N, N-diethyldithiocarbamate (DDTC) and the methyl ester of DDTC (Me-DDTC). AC-DDTC was very unstable in vivo and could not be detected neither in plasma nor in urine. Pharmacokinetic parameters of DDTC following intravenous administration of AC-DDTC (20 mg/kg) were calculated. DDTC has a low affinity to rat tissue and the body clearance was $9.0{\pm}3.4mkl/mim/kg$. The mean residence time (MRT) was $11.5{\pm}16.3 min$. After oral administration of 20 mg/kg AC-DDTC, maximal plasma concenttion ($C_{max}$) was $3.8{\pm}0.2 nmol/ml$ and the bioavailability was 7.04%. $C_{max}$ for DDTC at a dose of 120 mg/kg. AC-DDTC was $40.1{\pm}2.2 nmol/ml$. ART was $47.1{\pm}2.8min$.at a dose of 20 mg/kg and $110.5{\pm}6.0 min$ at 120 mg/kg.

• Archives of Pharmacal Research
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• 제17권5호
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• pp.354-359
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• 1994

The activity of SD-framesylcysteine O-methyltransferase was assayed by incubating the enzyrne with a synthetic in vitro substrate, [N-acetyl-S-trans, trns-famesyl-L-cysteine (AFC)], together with S-adenosyl-L-[emthyl-$_{14}$C)ester(AFCME)], was then analyzed either directly on HPLC or by converting the AFC[$methyl^{14}C$]ME to [$methyl^{14}C$] aclcohol by basehydrolysis. Employing these two analytical methods, it was established that a peptide purifed from rat liver cytosol fraction [Int. J. Biochem., 25, 1157 919930] strongly inhibited the above enzyme activity with $IC_{50}\; of\; 7.1\times 10^{-8}$ M. Also, the S-famesylcysteine O-methyltransferase from several human colon cancer cells was equally inhibited by the peptide.

• 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.

• KSBB Journal
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• 제23권6호
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• pp.519-524
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• 2008

Monacolin-K는 Monascus sp.로부터 polyketide pathway를 통해 생합성 되는 이차대사산물로써 강력한 콜레스테롤 저하제로 알려져 있다. 본 연구에서는 monacolin-K의 생합성 경로에 대한 이해에 근거한 지속적인 rational screening을 통해 monacolin-K의 생산성을 향상시킬 수 있었는데 그 중에서 특히 monacolin-K 생합성에 관련된 전구체를 최적화된 생산배지에 첨가함으로써 monacolin-K 생산성이 대조군에 비해 눈에 띠게 증가하는 결과를 확인하였다. 황의 동화작용에서 cysteine이 여러 단계를 거쳐 S-adenosylmethionine (SAM)으로 전환된다는 연구결과와 더불어, SAM은 다양한 세포내에서 주된 methyl donor 역할을 하므로 monacolin-K 구조에 포함되어있는 많은 methyl기 역시 SAM으로부터 유래한다고 알려져 있다. 따라서 첨가한 cysteine이 SAM을 생합성하는데 이용된 것으로 보고 SAM을 생산균주 내에서 고농도로 생산한다면 monacolin-K 생산성이 증가할 것이라 기대하였다. 따라서 여러 균주에서 보고된 SAM synthetase 유전자를 cloning하여 생산균주 내로 도입함으로써 생산균주가 cysteine의 별도첨가 없이도 세포내에서 SAM을 고농도로 생산하도록 하여 monacolin-K의 생산성 향상을 꾀하고자 하였다. 이를 위해 염기서열이 밝혀진 균사형성 곰팡이인 Aspergillus nidulans로부터 SAM synthetase를 암호화하는 metK 유전자를 cloning하고 Monascus 유래의 gpdA promoter에 의해 발현되도록 하는 재조합 발현벡터 pBMmetK를 제작하였고 이를 생산균주 내로 도입하여 형질전환체와 대조군의 monacolin-K 생산성을 확인한 결과, 대조군에 비해 형질전환체에서 Monacolin-K 생산성이 약 3.3배가량 증가한 것을 관찰하였다. 이는 metK 유전자가 생산균주의 DNA 내로 삽입되어 안정적으로 발현됨으로써 세포내에서 많은 methyl 기를 제공함으로써 monacolin-K 생산성이 향상된 것으로 판단되며, 현재는 분자적 수준에서 이러한 형질전환체 내에서 metK 유전자의 발현 정도를 확인하는 중이다.

• 한국식품저장유통학회지
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• 제16권6호
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• pp.929-937
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• 2009

본 연구에서는 국내산 Allium속의 휘발성 유기성분과 생리적 유용성을 지닌 함유황 유기화합물을 비교 분석하였다. 마늘, 양파 및 대파를 동결 건조하여 SDE 추출법을 이용하였으며 휘발성 유기성분을 추출하고 GC/MS로 분석하였다. 건마늘의 주요 향기성분은 diallyl disulfide, diallyl trisulfide, allyl methyl trisulfide, allyl methyl disulfide 등이었으며, 건양파에서는 dipropyl trisulfide, methyl propyl trisulfide 및 propanethiol 등이 확인되었다. 건대파에서는 dipropyl trisulfide, propanethiol, (E)-propenyl propyl disulfide, 3,5-diethyl-1,2,4-trithiolane, (Z)-propenyl propyl disulfide 및 propylene sulfide 등이 검출되었다. 전체적으로 모든 시료에서 함유황 유기화합물의 비율은 절반 이상으로 확인되어 특유의 휘발성 특징을 나타내는 것으로 확인되었으며 양파, 대파와 달리 마늘에서는 주로 (+)-S-(2-propenyl)-L-cysteine sulfoxide (ALLYL CSO, alliin)를 함유한 것에 기인하여 allyl group이 다량 확인되었다.

• Journal of Plant Biotechnology
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• 제5권1호
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• pp.33-41
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• 2003

Microspore-derived cell lines resistant to 5-methyltryptophan (5MT, a tryptophan analog) or S-(2-aminoethyl)-L-cysteine (AEC, a Iysine analog) were selected in rice by in vitro mutagenesis. For selection of 5MT or AEC resistant cell lines, suspension-cultured cells were irradiated with gamma rays. Thirteen 5MT resistant cell lines were selected and they were able to grow stably at 2 times higher 5MT concentration. A feedback insensitive form of anthranilate synthesis, the pathway specific control enzyme for tryptophan synthesis, was detected from the 5MT resistant lines. Contents of the free amino acids in five resistant lines (MR12-1 to MR12-5) showed a 7.4 to 46.6 times greater level than that in the control culture. Tryptophan, phenylalanine, and tyrosine levels in the shikimate pathway were 28.1 and 22.5 times higher in MR12-3 and MR12 4, respectively, than that measured in the control cells. Four AEC resistant cell lines were isolated from cultures grown on medium containing 1 mM AEC, They were able to grow stably with 2 mM AEC, while sensitive calli were inhibited by 0.5 mM AEC. Aspartate kinase activities of the resistant lines were insensitive to the natural inhibitor, Iysine, and accumulated 2.2 to 12.9-fold higher levels of free Iysine than that of the control cells. Especially, the levels of aspartate, asparagine, and methionine in the aspartate pathway showed higher accumulation in the AEC resistant lines than that in the control cells.