Kinetics and inhibition studies of catechol O-methyltransferase from the yeast Candida tropicalis

Veser, J.

doi:10.1128/jb.169.8.3696-3700.1987

Cited by 37 publications

(19 citation statements)

References 28 publications

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“…The preferential use of manganese by CthHen1 is intriguing, but not without precedent among metal-dependent O-methyltransferase enzymes (Kauss and Hassid 1967;Veser 1987;Kelm et al 1998;Lukacin et al 2004). The exemplar of the metal-dependent O-methyltransferase clade is catechol O-methyltransferase (COMT), which transfers the methyl group from AdoMet to one of two vicinal hydroxyl groups on the catechol ring.…”

Section: Mechanistic Implicationsmentioning

confidence: 99%

Bacterial Hen1 is a 3′ terminal RNA ribose 2′-O-methyltransferase component of a bacterial RNA repair cassette

Jain¹,

Shuman²

2009

RNA

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Hen1 is an RNA ribose 29-O-methyltransferase that modifies the 39 terminal nucleoside of eukaryal small regulatory RNAs. Here, we report that Hen1 homologs are present in bacterial proteomes from eight different phyla. Bacterial Hen1 is encoded by the proximal ORF of a two-gene operon that also encodes polynucleotide kinase-phosphatase (Pnkp), an RNA repair enzyme. Purified recombinant Clostridium thermocellum Hen1 is a homodimer of a 465-amino acid polypeptide. CthHen1 catalyzes methyl transfer from AdoMet to the 39 terminal nucleoside of an RNA oligonucleotide, but is unreactive with a synonymous DNA oligonucleotide or an RNA with a single 39-terminal deoxyribose sugar. CthHen1 is optimally active at alkaline pH and dependent on manganese. Activity is inhibited by AdoHcy and abolished by mutations D291A and D316A in the putative AdoMet-binding pocket. The C-terminal fragment, Hen1-(259-465), comprises an autonomous monomeric methyltransferase domain.

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Section: Mechanistic Implicationsmentioning

confidence: 99%

Bacterial Hen1 is a 3′ terminal RNA ribose 2′-O-methyltransferase component of a bacterial RNA repair cassette

Jain¹,

Shuman²

2009

RNA

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“…ase (13)(14)(15). And it is also effective in the cytoprotection of hepatocytes (16), kidney cells (14), cardiac cells (17).…”

Section: Introductionmentioning

confidence: 99%

Anti-inflammatory functions of purpurogallin in LPS-activated human endothelial cells

Kim¹,

Ku²,

Lee³

et al. 2012

BMB Reports

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Enzymatic oxidation of commercially available pyrogallol was efficiently transformed to an oxidative product, purpurogallin. Purpurogallin plays an important role in inhibiting glutathione S-transferase, xanthine oxidase, catechol O-methyltransferase activities and is effective in the cell protection of several cell types. However, the anti-inflammatory functions of purpurogallin are not well studied. Here, we determined the effects of purpurogallin on lipopolysaccharide (LPS)-mediated proinflammatory responses. The results showed that purpurogallin inhibited LPS-mediated barrier hyper-permeability, monocyte adhesion and migration and such inhibitory effects were significantly correlated with the inhibitory functions of purpurogallin on LPS-mediated cell adhesion molecules (vascular cell adhesion molecules, intracellular cell adhesion molecule, E-selectin). Furthermore, LPS-mediated nuclear factor-κB (NF-κB) and tumor necrosis factor-α (TNF-α) releases from HUVECs were inhibited by purpurogallin. Given these results, purpurogallin showed its anti-inflammatory activities and could be a candidate as a therapeutic agent for various systemic inflammatory diseases. [BMB reports 2012; 45(3): [200][201][202][203][204][205]

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“…It was also revealed that the used concentration range of ES did not deviate from linearity. From this experiment, K m values both for SAM and ES was obtained as 3.5 ± 0.3 M and 6.4 ± 0.4 M which was reported as 6.2 M in Veser's study [8].…”

Section: Kinetic Analysis To Determine Enzyme-substrates Relationshipmentioning

confidence: 95%

“…Enzymatic assays were performed according to the method reported by J. Veser's and M. Kurkela et al's studies with minor differences by using Microfluor white, 96 well plate [8,9]. The followed reaction which was catalyzed by COMT was conversion of aesculetin to scopoletin at 37 • C. Aesculetin was dissolved in dimethyl sulfoxide (DMSO) and diluted with aqueous buffer solution containing 100 mM phosphate, 5 mM MgCl 2 , 20 mM l-cysteine (pH 7.4), for a final DMSO concentration of 2% in the 200 l of reaction mixture.…”

Section: Determination Of Enzyme Activity and Inhibition Studymentioning

confidence: 99%

Inhibition of catechol-O-methyltransferase (COMT) by some plant-derived alkaloids and phenolics

Yalçın

Bayraktar

2010

Journal of Molecular Catalysis B: Enzymatic

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a b s t r a c tIn this study, as an alternative to the medicines, natural compounds extracted from plant species (Peganum harmala, Cistus parviflorus and Vitex agnus-cactus) were investigated in order to inhibit the catechol-O-metyhltranferase (COMT) activity. In fluorometric enzyme assay, S-adenosylmethionine (SAM) and aesculetin (ES) were used as methyl donor and acceptor substrates, respectively. Their K m values were determined as 3.5 ± 0.3 M and 6.4 ± 0.4 M in absence of inhibitor. Inhibition performances of the plantderived polyphenolics and alkaloids were determined. Inhibitory effect of alkaloids extracted from P. harmala seeds was found the highest among the plant extracts; however, it was lower than that of 3,5-DNC. In case of inhibition mechanism, mixed type inhibition was observed for alkaloid extract whereas uncompetitive inhibition was observed for 3,5-DNC. In case of polyphenolic extracts obtained from C. parviflorus and V. agnus-cactus leaves, mechanism were also explained as mixed type inhibition and their K i values were calculated as 1.99 ± 0.35 g/ml and 9.48 ± 0.58 g/ml, respectively.

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Kinetics and inhibition studies of catechol O-methyltransferase from the yeast Candida tropicalis

Cited by 37 publications

References 28 publications

Bacterial Hen1 is a 3′ terminal RNA ribose 2′-O-methyltransferase component of a bacterial RNA repair cassette

Bacterial Hen1 is a 3′ terminal RNA ribose 2′-O-methyltransferase component of a bacterial RNA repair cassette

Anti-inflammatory functions of purpurogallin in LPS-activated human endothelial cells

Inhibition of catechol-O-methyltransferase (COMT) by some plant-derived alkaloids and phenolics

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