• Journal of Life Science
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• v.21 no.1
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• pp.96-101
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• 2011

S-Adenosyl-L-methionine synthtase (SAM-s) catalyzes the biosynthesis of SAM from ATP and L-methionine. SAM plays important roles in the primary and secondary metabolism of cells. A metK encoding a SAM-s was searched from Streptomyces natalensis producing natamycin, a predominantly a strong antifungal agent, inhibiting the growth of both yeasts and molds and preventing the formation of aflatoxin in filamentous fungi. To obtain the metK of S. natalensis, PCR using primers designed from the two highly conserved regions for metK genes of Streptomyces strains was carried out, and an intact 1.2-kb metK gene of S. natalensis was cloned by genomic Southern hybridization with PCR product as a probe. To identify the function of the cloned metK gene, it was inserted into pSET152ET for its high expression in the Streptomyces strain, and then introduced into S. lividans TK24 as a host by transconjugation using E. coli ET12567(pUZ8002). The high expression of metK in S. lividans TK24 induced actinorhodin production on R5 solid medium, and its amount in R4 liquid medium was 10-fold higher than that by exconjugant including only pSET152ET.

• Food Science of Animal Resources
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• v.34 no.1
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• pp.65-72
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• 2014

This study is executed to develop probiotics which produce S-adenosyl-L-methionine (SAM), a methyl group donor of the 5-methyltetrahydrofolate methylation reaction within the animal cell. SAM is an essential substance for the synthesis, activation, and metabolism of hormones, neurotransmitters, nucleic acids, phospholipids, and cell membranes of animals. The SAM is also known as a nutritional supplement to improve brain functions of the human. In this study, the SAM-producing strains are identified in 18 types of salted fish, and then, the strains with excellent SAM productions are being identified, with 1 strain in the Enterococcus genus and 9 strains in the Bacillus genus. Strains with a large amount of SAM production include the lactic acid bacteria such as En. faecium and En. durans, En. sanguinicola, as well as various strains in the Bacillus genus. The SAM-overproducing strains show antibacterial activities with certain harmful microbes in addition to the weak acid resistances and strong bile resistances, indicating characteristics of probiotics. It is possible that the jeotgal-originated beneficial strains with overproducing SAM can be commercially utilized in order to manufacture SAM enriched foods.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.505.2-506
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• 1986

L-Azetidine-2-carboxylic acid (A-2-C), a four-membered cyclic imino acid has been identified in certain plants, and the microorganism Actinoplanes ferrugineus. The imino acid A-2-C has a physiological significance as an antgaonist of proline during peptide synthesis. The biosynthetic mechanism for the formation of A-2-C has not been studied in any detail. By using various amino acids such as methionine and S-adenosyl-L-methionine labeled with deuterium or carbon-14, the details of the biosynthetic pathway and a possible mechanism for the formation of L-A-2-C in .4. ferrugineus have been unravelled, Both in vivo and in vitro experimental results suggest the biosynthesis of L-A-2-C is mediated by a confactor containing a carbonyl group, probably pyridoxal Phosphate. S-Adenosyl-L-methionine, which seems to be the direct biosynthetic substrate, has undergone a f-displacement by an ${\alpha}$-amino group of the amino acid portion of the substrate S-adenosyl-L-methionine potentially via a vinylglycine intermediate. The overall stereochemical events at the ${\beta}$-carbon of the substrate have been shown to inversion of configuration. The overall stereochemical events at the -position of the sub- strate have also been shown to occur with inversion of configuration. The ${\beta}$, ${\gamma}$-elimination reaction of the substrate seems to follow a cisoidal-type mechanism and the addition portion of the reaction a transoidal-type mechanism . The assignment of the proton NMR of A-2-C has been deduced by apply- ing NOE difference experiments, Gd(III) line-broadening experiments and 2D-NOESY experiments of regio-and stereospecificially deuterated A-2-C's.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.235.3-236
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• 2003

S-adenosyl-L-homocysteine(AdoHcy) is the product of all biological methylation in which S-adenosyl-L-methionine (AdoMet) is utilized as a methyl donor and is reversibly hydrolyzed to L-homocysteine and adenosine by AdoHcy hydrolase physiologically. Inhibition of this enzyme results in intracelluar accumulation of AdoHcy leading to a feedback inhibition of AdoMet-dependent methylation reactions which are essential for viral replication. (omitted)

• Food Science and Biotechnology
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• v.17 no.5
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• pp.1025-1031
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• 2008

S-Adenosyl-L-methionine (SAM) exerts several beneficial effects on depression, chronic diseases, and cognitive impairments. Bifidobactrium bifidum BGN4 reportedly produces higher amounts of SAM than any other lactic acid bacterium used in yogurt. The aim of this study was to develop a SAM-reinforced probiotic yogurt using Bifidobacterium. The sensory aspects of the yogurt via response surface methodology (RSM) and the texture and SAM content of the yogurt were assessed. Based on the sensory assessments for sweetness, sourness, and thickness evaluated by 48 panelists, the optimized conditions for preparation of SAM-reinforced yogurt were 4.0-4.4%(w/w) sugar, 3.2-3.5%(w/w) skim milk, and a pH of 4.7-4.8. The SAM content of the developed yogurt was 0.05 nmol/mL. In conclusion, SAM-reinforced probiotic yogurt may provide a vehicle for the potential exploitation of the benefits of increased dietary SAM.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.301-304
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• 2005

S-Adenosyl-L-Methionine(SAM) has an important role for DNA methylation and cell signaling. SAM was synthesized from methionine and ATP by SAM synthetase and play an pivotal function in the primary and secondary metabolism of cells. Recent studies have revealed in the effect of SAM in case of morphological differentiation in both eukaryotes and prokaryotes. We isolated SAM gene from Saccharomyces cerevisiae and cloned it into expression vector for E. coli respectively. An 1.15 kb SAM-s gene fragment was isolated by Low-strigency PCR using ORF primer. By the analysed primary sequence deduced from DNA sequence, this gene included conserved domains similar with other well-known SAM synthetase. First of all, SAM synthetase gene cloned pGEM-T vector and subcloned into histidine tagging system to purify the expressed protein using metal chelating resin. Typical characteristic analysis of this enzyme is underway.

• Korean Journal of Food Science and Technology
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• v.41 no.4
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• pp.417-422
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• 2009

The purpose of this study was to measure the changes in S-adenosyl-L-methionine (SAM) content and to find the best condition for SAM Kimchi during fermentation with the different kinds of raw materials of Kimchi and the diverse ways of making Kimchi. As fermentation was processing, pH of all Kimchi groups dramatically decreases at the beginning stage of experimentation. However, pH value was 4.2-4.3 in the last stage. Titratable acidity tends toward the similar results in pH value. At the first, the SAM content went down time substantially and then increases. Kimchi (A), which was made of the most basic raw materials, resulted in the lowest content of SAM. The most abundant SAM content of Kimchi was the Kimchi made with certain materials. Kimchi (I) had the most has SAM content, overall. The best time of fermentation was when pH was between 4.3 and 5.3, and titratable acidity was 0.5-1.0%. As the results of this study, the highest SAM content in Kimchi could be made when Kimchi was fermented for 9-12 days and titratable acidity showed 0.5-1.0% This study proved that the ratio of raw materials such as red pepper, fermented fished sauces, and other materials improved the levels of SAM in the Kimchi.

• YAKHAK HOEJI
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• v.36 no.1
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• pp.66-72
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• 1992

In order to test relationships between hepatotoxicity and transmethylation, activities of protein methylases and SAM (S-adenosyl-L-methionine)-synthetase were examined in liver tissues of rats treated with $CCl_4$. Also the concentrations of SAM and SAH were measured by HPLC in rat liver. The results are as follows. (1). Activities of protein methylases were not significantly changed in 24 hours after $CCl_4$ treatment. However, in 48 hours, activities of protein methylases were significantly increased in comparison with that of control. (2). Activity of SAM-synthetase was increased steadily in the time course after $CCl_4$ treatment. (3). S-adenosyl-L-methionine concentration of liver tissues in $CCl_4$-treated group was elevated in 24 hours, and then declined thereafter. But the SAH concentration was slightly decreased in the time course after $CCl_4$ treatment. These results indicate that SAM was very actively used in transmethylation reactions of $CCl_4$ damaged rat liver, suggesting the strong relationships between hepatotoxicity and transmethylation phenomena.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.505.1-505
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• 1986

The gene for iso-1-cytochrome c for Saccharomyces cerevisiae was recloned into a pSP65 vector containing an active bacteriophage SP6 promoter. The iso-1-cytochrome c gene was cloned as an 856 bp Xho 1-Hind III fragment. When the resulting plasmid was digested at the Hind 111 site 279 bases downstream from the termination codon of the gene and transcribed in vitro using SP6 RNA polymerase, full length transcripts were produced. The SP6 iso-1-cytochrome c mRNA was translated using a rabbit reticulocyte lysate system and the protein products analyzed on SDS polyacrylamide gels. One major band was detected by autofluorography. This band was found to have a molecular weight of 12,000 Da and coincided with the Coomassie staining band of apocytochrome c from S. cerebisiae. The product was also shown to be identical with that of standard yeast apocytochrome c on an isoelectric focusing gel. The in vitro synthesized iso-a-cytochrome c was methylated by adding partially purified S-adenosyl-L-methionine . protein-lysine N-methyltransferase (Protein methylase III; EC 2.1.1.43) from S. cerevisiae along with S-adenosyl-L-methionine to the in vitro translation mixtures. The methylation was shown to be inhibited by the addition of the methylase inhibitor S-adenosyl-L-homocysteine or the protein synthesis inhibitor pu omycin. The methyl derivatives in the protein were identified as $\varepsilon$-N-mono, di and trimethyllysine by amino acid analysis. The molar ratio of methyl groups incorporated to that of cytochrome c molecules synthesized showed that 23% of the translated cytochrome c molecules were methylated by protein methylase III.

• Archives of Pharmacal Research
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• v.8 no.3
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• pp.149-157
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• 1985

The HCL hydrolyzate of the non-histone protein fractionated from the rat liver nuclei which have been incubated inthe presence of S-adenosyl-L-[methyl-$^{14}C$ ]-methionine shows at least four unidentified radioactive peaks on a basic amino acid analysis chromatogram. One of these unknown compounds (designated as compound 3) is also formed by the rat liver homogenated with the exogenous addition of an appropriate protein substrate. Since boiled rat liver homogenate or fresh homogenate in the absence of an exogenous protein substrate failed to form compound 3, its formation can be considered to be enzyme-catalyzed. The enzyme which yields compound 3 shows a preference of protein substrate in the order of reductively methylated hemoglobin > native > histone type II-A. The rat enzyme is nuclear in location associated with chromatin, and exhibits the highest activity in the liver among various rat organs. A compound 3-forming enzyme is also present in Neurospora crassa, since endogenous formation of the compound 3 can be demonstrated with the crude extract of this mold. The chemical identity of compound 3 is not yet known. However, it resisted to the following treatments; 6 N HCL and 0.1 N Na NaOH hydrolysis at $110^{\circ}C$, OR L-amino acid oxidase.