• 약학회지
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• 제38권4호
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• pp.430-439
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• 1994

S-Adenosyl-L-methionine synthetase (ATP: methionine S-Adenosyltransferase, EC 2.5.1.6; AdoMet synthetase) catalyzes the biosynthesis of S-Adenosyl-L-methionine(AdoMet) from methionine in the presence of ATP. To elucidate the role of transmethylation reaction in the pancreatic tissues, we examined AdoMet synthetase and isozyme activities, and AdoMet contents in the various tissues. The activities of AdoMet synthetase marked the highest in the kidney, and the lowest in the testis among the various tissues of rat. Considerable amounts of AdoMet synthetase activities were detected in the pancreatic tissues of various animals except for those of frog. The level of ${\alpha}$ and ${\gamma}$ isozyme activities were present in the pancreatic tissues of various animals, while ${\beta}$ isozyme activities were detected as trace. AdoMet synthetase activities of rat brain, liver, testis were decreased with growth. In the rat pancreatic tissues, AdoMet synthetase activities were increased during 16 days after birth and then decreased between 16 and 47 days of age. Levels of AdoMet contents of rat brain and testis were decreased with growth. However, AdoMet contents of rat pancreas were decreased until 26 days of age, and then increased thereafter. AdoMet synthetase isozyme patterns did not vary with growth in the pancreas and testis. But, in the liver, ${\beta}$ form is strikingly increased with growth.

• BMB Reports
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• 제28권2호
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• pp.100-106
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• 1995

S-adenosylmethionine (SAM) synthetase was purified to homogeneity from soybean (Glycine max) axes. The enzyme was purified 216-fold with a 1.5% yield by ammonium sulfate fractionation, acetone fractionation, ion exchange chromatography with DEAE-sephacel, gel filtration with Sephacryl S-300, and afffinity chromatography with ATP-agarose. The enzyme activity reached a maximum 3 days after germination. SAM synthetase had a subunit molecular weight of 57,000 daltons from a silver stained single band on SDS-PAGE. The molecular weight of the enzyme was 110,000 daltons from Sephacryl S-300 gel filtration. The enzyme was composed of two identical subunits. The $K_m$ values of the enzyme for L-methionine and ATP were 1.81 and 1.53 mM, respectively. The enzymatic activity was not affected by polyamines, agmatine, or SAM analogues, but was inhibited by SAM. The inhibition pattern was showed non-competitive for L-methionine and uncompetitive for ATP. The activity of SAM synthetase was inhibited by thiol-blocking reagents. The enzyme was induced by treatment with $10^{-3}$ M putrescine at germination. Experimental data revealed a possible novel regulation mechanism of polyamine biosynthesis through several endogenous intermediates.

• Journal of Microbiology and Biotechnology
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• 제33권3호
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• pp.310-318
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• 2023

Microalgae are attracting much attention as promising, eco-friendly producers of bioenergy due to their fast growth, absorption of carbon dioxide from the atmosphere, and production capacity in wastewater and salt water. However, microalgae can only accumulate large quantities of lipid in abiotic stress, which reduces productivity by decreasing cell growth. In this study, the strategy was investigated to increase cell viability and lipid production by overexpressing S-adenosylmethionine (SAM) synthetase (SAMS) in the microalga Chlamydomonas reinhardtii. SAM is a substance that plays an important role in various intracellular biochemical reactions, such as cell proliferation and stress response, and the overexpression of SAMS could allow cells to ithstand the abiotic stress and increase productivity. Compared to wild-type C. reinhardtii, recombinant cells overexpressing SAMS grew 1.56-fold faster and produced 1.51-fold more lipids in a nitrogen-depleted medium. Furthermore, under saline-stress conditions, the survival rate and lipid accumulation were 1.56 and 2.04 times higher in the SAMS-overexpressing strain, respectively. These results suggest that the overexpression of SAMS in recombinant C. reinhardtii has high potential in the industrial-scale production of biofuels and various other high-value-added materials.

• Journal of Microbiology and Biotechnology
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• 제21권8호
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• pp.854-857
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• 2011

POMT7, which is an O-methyltransferase from poplar, transfers a methyl group to several flavonoids that contain a 7-hydroxyl group. POMT7 has been shown to have a higher affinity toward quercetin, and the reaction product rhamnetin has been shown to inhibit the formation of beta-amyloid. Thus, rhamnetin holds great promise for use in therapeutic applications; however, methods for mass production of this compound are not currently available. In this study, quercetin was biotransformed into rhamnetin using Escherichia coli expressing POMT7, with the goal of developing an approach for mass production of rhamnetin. In order to maximize the production of rhamnetin, POMT7 was subcloned into four different E. coli expression vectors, each of which was maintained in E. coli with a different copy number, and the best expression vector was selected. In addition, the S-adenosylmethionine biosynthesis pathway was engineered for optimal cofactor production. Through the combination of optimized POMT7 expression and cofactor production, the production of rhamnetin was increased up to 111 mg/l, which is approximately 2-fold higher compared with the E. coli strain containing only POMT7.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2006년도 한국약용작물학회 공동춘계학술발표회
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• pp.182-183
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• 2006

• 원예과학기술지
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• 제30권6호
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• pp.734-742
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• 2012

본 연구는 배추의 유전자 기능분석을 위한 RNAi 유전자 침묵 기법과 T-DNA 삽입 기법을 비교하기 위해 수행하였다. 두 종류의 형질전환 계통이 이용되었으며 BrSAMS-knockout(KO) 계통은 T-DNA 삽입으로 한 개의 Brassica rapa S-adenosylmethionine synthetase(BrSAMS) 유전자가 기능을 상실한 계통이었으며 BrSAMS-knockdown(KD) 계통은 RNAi 방법을 통해 BrSAMS 유전자들의 발현이 억제된 계통이었다. KO 계통과 KD 계통의 microarray 분석 결과에서는 SAMS 유전자와 관련된 sterol, 자당, homogalacturonan 생합성 및 glutaredoxin-related protein, serine/threonine protein kinase, 그리고 gibberellin-responsive protein 유전자들의 발현 수준이 뚜렷한 차이를 보여 주었다. 그러나 KO 계통의 유전자 발현 양상은 하나의 BrSAMS 유전자가 기능을 상실하였음에도 불구하고 대조 계통과 비교하여 RNAi기법을 적용한 KD 계통에 비해 큰 차이를 보여주지 못했다. 또한 직접적으로 SAMS 유전자와 관련된 폴리아민과 에틸렌 합성 유전자들의 발현 변화도 KD 계통에서 더 잘 나타났다. 본 연구에서 microarray 결과를 이용한 KO 계통의 BrSAMS 기능분석은 배추과식물의 게놈 triplication 발생으로 인하여 다수로 존재하는 SAMS 유전자들 때문에 명확한 결론을 얻을 수 없었다. 결론적으로 배추와 같은 배수체 작물의 유전자 기능 분석은 RNAi silencing에 의한 유전자 knock-down 기법이 T-DNA 삽입에 의한 knock-out 기법보다 더욱 효율적인 것으로 나타났다.

• 통합자연과학논문집
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• 제1권3호
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• pp.230-233
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• 2008

A simple and rapid method is described for extending the 5'- or 3'-end genomic sequence of a known partial sequence by only a single round of PCR. This method involves digesting and ligating genomic and plasmid DNAs, and amplifying the 5'-upstream or 3'-end downstream sequence of the known DNA sequence, using two primers, one gene specific and the other plasmid specific. A single round of PCR amplification is sufficient to produce gene-specific bands detectable in gels. By using this approach, 5'-end genomic sequence of the D-amoeba sams gene was extended.

• 한국산학기술학회논문지
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• 제14권7호
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• pp.3582-3588
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• 2013

A. tamarense로부터 ESTs library를 제작하였다. 이들의 염기서열을 분석하여 STX 생합성 관련 유전자를 클로닝하였다. 연구결과 827 클론의 염기서열이 분석되었고, 564개의 EST가 GenBank에서의 Blast search를 사용하여 기능에 따라 분류되었다. EST에서의 주요 유전자는 cellular organization, cell metabolism, energy, cell cycle과 DNA processing, cellular transport와 transport, cell rescue, defense, death와 aging 및 transcription 등으로 분석되었다. 특히 S-adenosylmethionine synthetase와 H2A histone family 유전자의 발현이 독성 A. tamarense에서 증가하였다. 이러한 결과는 두 개의 유전자가 A. tamarense에서의 삭시톡신 생합성을 검출하기 위한 좋은 바이오마커가 될 수 있음을 보여준다.

• 생명과학회지
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• 제21권1호
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• pp.96-101
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• 2011

ATP와 L-methionine으로부터 SAM synthetase (MetK)에 의해 생합성 되는 S-adenosylmethionine (SAM)은 세포내 메틸화에 필요한 메틸기를 제공하는 중심적인 공급체의 역할을 할뿐만 아니라 방선균에서는 일차 및 이차대사산물의 생산 조절에 관여하고 있다는 사실이 밝혀졌다. 이에 논 연구에서는 산업적으로 매우 중요한 항진균성 항생물질인 natamycin을 생산하는 S. natalensis로부터 SAM synthetase 코드하는 metK 유전자를 클로닝하고 동정하였다. S. natalensis에서 클로닝된 metK는 1,209 bp의 염기를 가진 유전자로써 아미노산서열에서 S. pristinaespiralis ATCC 25486과 S. peucetius ATCC 27952의 MetK와 96%, S. violaceusniger Tu 4113과 95% 일치하는 매우 높은 상동성을 보였다. 또 pSET152ET 벡터를 이용해 구축한 metK 고발현용 재조합 플라스미드 pCD1를 S. lividans TK24의 genomic DNA에 도입하여 actinorhodin 생산 유도를 시도해 본 결과 R5 고체배지에서 pCD1이 도입되지 않은 균주에서는 actinorhodin 생산을 전혀 확인할 수 없었지만 pCD1이 도입된 형질전환체에서는 actinorhodin 생산이 강하게 유도되었으며 R4 액체배지에서는 actinorhodin 생산량이 10배 증가되었다. 따라서 본 연구를 통해 클로닝된 S. natalensis 유래 metK 유전자는 방선균에서 이차대사산물의 생산을 유도할 수 있음을 확인할 수 있었다.

• Journal of Crop Science and Biotechnology
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• 제10권1호
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• pp.50-56
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• 2007

Barley S-adenosylmethionine synthetase1 gene, which was differentially expressed in seed development of extra early barley, was regulated by the phytohormones and abiotic stresses. In order to identify the regulation regions which were involved in transcriptional control of the phytohormones and abiotic stresses, we isolated 1459 bp fragment of HvSAMS1 gene promoter using genome walking strategy and deletion series were constructed. Deleted upstream fragments(-1459, -1223, -999, -766, -545, -301 bp) were fused to the GUS reporter gene and evaluated via Agrobacterium-mediated transient expression assay. Increased GUS activity of HvSMAS1 promoter -301/GUS construct under each of NaCl, $GA_3$, ABA and ethylene application was found. However, GUS activity was negligible in the leaves transformed with the HvSMAS1 promoter(-1459, -1223, -999, -766 and -545)/GUS constructs. No significant induction of GUS activity was observed for the ethionine and spermidine treatments. In order to locate promoter sequence of the HvSAMS1 gene that was critical for the activation of gene expression, deletion and addition promoter derivatives(+, includes 43 bp of 5' ORF) of the HvSAMS1 gene fused to the GUS reporter gene were applied. The tobacco leaves which harbored the additional HvSAMS1 promoter(-1459+, -1459 to -546, -545+ and -301+)/GUS construct did not significantly induce GUS activity as compared to the HvSAMS1 promoter(-1459, -545 and -301)/GUS constructs under each of NaCl, ABA and $GA_3$ treatment. However, the GUS activity was high in the tobacco leaves which harboring the -211 to -141 regions of the HvSAMS1 promoter. This result suggested that HvSAMS1 gene expression might be regulated by this region(from -211 to -141).