• Bulletin of the Korean Chemical Society
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• v.26 no.1
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• pp.171-174
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• 2005

• 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)

• FLOWER RESEARCH JOURNAL
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• v.18 no.4
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• pp.278-283
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• 2010

This study was conducted to investigate the involvement of flower abnormality and S-adenosyl-L-homocysteine hydrolase (SAHH), which is one of the key enzyme in the maintenance of methylation. Plants exposed to high temperature (HT) and long day (LD) condition from 14-27days after short day (SD) produced abnormal flower, having numbers of ray florets. Numbers of ray florets were increased more than 2 folds by HT of $35/20^{\circ}C$ and LD of 14 hour comparing those of $25/20^{\circ}C$ (12 h/12 h). Full-length cDNA clone of S-adenosyl-L-homocysteine hydrolase (DgSAHH) in spray chrysanthemum 'Lerbin' contained an 1455 bp open reading frame coding for 485 amino acids. It showed highly conserved coding sequences among the different plant species with over 90% homology. DgSAHH expression was decreased in abnormal flower inducing treatment of HT and LD, while DgSAHH transcripts accumulated in flower bud of non abnormality inducing condition. This result implicate that DgSAHH expression is affected by temperature and photoperiod during flower development and suppression of DgSAHH is a one of the cause of abnormal flower under HT and LD condition.

• Journal of Microbiology and Biotechnology
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• v.16 no.7
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• pp.1154-1157
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• 2006

It is known that overexpression of S-adenosyl-L-methionine (SAM) synthetase or exogenous addition of SAM enhances the production of actinorhodin, one of pigmented antibiotics found from Streptomyces coelicolor. In order to discover a novel compound as a signal molecule to produce actinorhodin instead of SAM, several compounds were synthesized based on the relationships between structures of the SAM analogues and their actinorhodin productivities. Of these, a few compounds showed better productivities of actinorhodin than SAM.

• YAKHAK HOEJI
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• v.31 no.3
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• pp.173-181
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• 1987

Protein methylase I has been partially purified from hog pancreas with a 11% yeild. The final preparation is completely free of any other protein-specific methyltransferases and endogenous substrate proteins. The enzyme has an optimum pH of 7.2 and the approximate molecular weight is above 800 thousands dalton. The Km values for S-adenosyl-L-methionine and histone type II-A are 1.32$\times$10$^{-5}$M. The Ki value for S-adenosyl-L-homocysteine is 1.52$\times$10$^{-6}$M. The effect of enyzme concentration on the activity showed a slight sigmoidal curve suggesting the involvement of certain cofactors. Even though the purified enzyme showed two bands on polyacrylamide gel electrophoresis, the enzyme is highly specific for the arginine residues of protein and specifically, highly specific for histone, suggesting histonespecific protein methylase I.

• 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.

• Proceedings of the Korea Crystallographic Association Conference
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• 2003.05a
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• pp.17-17
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• 2003

tRNA (m¹ G37) methyltransferase (TrmD) catalyze s the trans for of a methyl group from S-adenosyl-L-methionine (AdoMet) to G/sup 37/ within a subset of bacterial tRNA species, which have a residue G at 36th position. The modified guanosine is adjacent to and 3' of the anticodon and is essential for the maintenance of the correct reading frame during translation. We have determined the first crystal structure of TrmD from Haemophilus influenzae, as a binary complex with either AdoMet or S-adenosyl-L-homocysteine (AdoHcy), as a ternary complex with AdoHcy/phosphate, and as an apo form. The structure indicates that TrmD functions as a dimer (Figure 1). It also suggests the binding mode of G/sup 36/G/sup 37/ in the active site of TrmD and catalytic mechanism. The N-terminal domain has a trefoil knot, in which AdoMet or AdoHcy is bound in a novel, bent conformation. The C-terminal domain shows a structural similarity to DNA binding domain of trp or tot repressor. We propose a plausible model for the TrmD₂-tRNA₂ complex, which provides insights into recognition of the general tRNA structure by TrmD (Figure 2).

• Archives of Pharmacal Research
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• v.21 no.4
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• pp.378-384
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• 1998

The processing pathway of G-proteins and Ras family proteins includes the isoprenylation of the cysteine residue, followed by proteolysis of three terminal residues and .alpha.-carboxyl methyl esterification of the cysteine residue. Farnesylcysteine methyltransferase (FCMT) activity is responsible for the methylation reaction which play a role in the membrane attachment of a variety of cellular proteins. Four kinds of Ras protein (c-Ha-ras, c-N-Ras, c-Ki-Ras, pan-Ras) expression were detected in adenocarcinoma of human tissue by immunohistochemical method, and hematoxylin and eosin staining. The level of Ras protein in human stomach tumor tissues was much higher than in normal and peritumoral regions of the same biopsy samples. The FCMT activities of each cellular fractions were high in mitochondrial fraction followed by microsomal fraction, whole homogenate and cytosolic fraction. The inhibitory effect on FCMT activity on stomach tumor tissue was determined after treatment with 0.25 $\mu\textrm{M}$ of S-adenosyl-$_L$-homocysteine. S-adenosyl-$_L$-homocysteine inhibited FCMT activity from 11.2% to 30.5%. These results suggested that FCMT might be involved in Ras proteins activity.

• BMB Reports
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• v.28 no.2
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• pp.149-154
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• 1995

Protein methylase II (S-adenosyl-L-methionine : protein O-methyl-transferase, EC 2.1.1.24; PM II) was purified approximately 1250-fold from porcine testis by fractional precipitation and DEAE-cellulose chromatography, followed by gel filtration on a Sephadex G-75 column and HPLC on a Protein Pak 125 column. The molecular weight of the enzyme was estimated to be 33,000 daltons by SDS-PAGE, which agreed with the value determined by gel filtration. Isoelectric focusing of purified PM II showed a single protein species with an isoelectric point of 6.2. The optimum pH for the reaction was 6.0. The $K_m$ value of the enzyme was $1{\times}10^{-5}M$ with a $V_{max}$ value of 769 pmol/min/mg of enzyme. S-adenosyl-L-homocysteine is a competitive inhibitor of PM II with a $K_i$ value of $1.38{\times}10^{-6}M$.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.186-190
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• 2002

S- Adenosylhomocysteine hydrolase $(SAH)^1$ catalyzes the hydrolysis of S-adenosylhomocysteine to adenosine and L-homocysteine. Inhibition of this enzyme accumulates S-adenosylhomocysteine, which in turn inhibits S-adenosyl-L-methionine dependent transmethylation, resulting in no formation of the capped methylated structure at the 5'-terminus of viral mRNA. Thus, S-adenosylhomocysteine hydrolase has been an attractive target for the development of broad spectrum of antiviral agents. (omitted)