Über eine ungewöhnliche Spaltung von Diaryl‐äthern

Mayer, Walter; Fikentscher, Rolf; Schmidt, Johannes; Schmidt, Otto

doi:10.1002/cber.19600931203

Cited by 13 publications

(3 citation statements)

References 14 publications

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“…The projected products of these reactions, the small molecule methylated species and the protein-bound methylated species shown above, can be degraded in a base to labilize the methyl group as volatile methanol. Here, Michael addition of hydroxide ion to the small molecule-methylated species can yield an intermediate species that can form methanol and regenerate the ortho-quinone by a ␤-elimination mechanism (47). Similar chemistry can give methanol from the proteinbound methylated species.…”

Section: Table 2 Endogenous Comt Activity In Mouse Cytosolic Extractsmentioning

confidence: 99%

S-Adenosylmethionine-dependent Protein Methylation in Mammalian Cytosol via Tyrphostin Modification by Catechol-O-methyltransferase

Lipson

Clarke

2007

Journal of Biological Chemistry

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It has previously been shown that incubation of mammalian cell cytosolic extracts with the protein kinase inhibitor tyrphostin A25 results in enhanced transfer of methyl groups from S-adenosyl-[methyl-3 H]methionine to proteins. These findings were interpreted as demonstrating tyrphostin stimulation of a novel type of protein carboxyl methyltransferase. We find here, however, that tyrphostin A25 addition to mouse heart cytosol incubated with S-adenosyl-[methyl- H]methionine or S-adenosyl-[methyl-14 C]methionine stimulates the labeling of small molecules in addition to proteins. Base treatment of both protein and small molecule fractions releases volatile radioactivity, suggesting labile ester-like linkages of the labeled methyl group. Production of both the base-volatile product and labeled protein occurs with tyrphostins A25, A47, and A51, but not with thirteen other tyrphostin family members. These active tyrphostins all contain a catechol moiety and are good substrates for recombinant and endogenous catechol-O-methyltransferase. Inhibition of catechol-O-methyltransferase activity with tyrphostin AG1288 prevents both base-volatile product formation and protein labeling from methyl-labeled S-adenosylmethionine in heart, kidney, and liver, but not in testes or brain extracts. These results suggest that the incorporation of methyl groups into protein follows a complex pathway initiated by the methylation of select tyrphostins by endogenous catechol-Omethyltransferase. We suggest that the methylated tyrphostins are further modified in the cell extract and covalently attached to cellular proteins. The presence of endogenous catechols in cells suggests that similar reactions can also occur in vivo.S-Adenosylmethionine-dependent protein methylation is a common post-translational modification, occurring at N-terminal amino, arginine, lysine, modified aspartyl, and C-terminal carboxyl residues (1). These reactions not only create additional diversity in protein amino acids but also provide opportunities for biological regulation by reversible modifications (2-9).We have been especially interested in identifying novel types of protein methylation reactions. In 1999, Bilodeau and Béliveau (10) -dependent protein methylation in rat kidney cytosolic extracts is greatly stimulated by the addition of the protein-tyrosine kinase inhibitor tyrphostin A25 and the protein phosphatase inhibitor sodium vanadate. These results suggested a regulatory interplay between protein phosphorylation and methylation systems. We were able to confirm these results in mouse kidney cytosol (11). We were also able to show that tyrphostin A25, in the presence or absence of vanadate, stimulates protein methylation in mouse heart cytosol, but not in testes or brain cytosol (11). Of a variety of tyrphostins tested only the A25 and A47 derivatives were active in stimulating protein methylation in kidney cytosol. Analysis of a 3 H-methylated 15-kDa polypeptide indicated that the radioactivity was not due to protein lysine or arginine methylation. The...

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Section: Table 2 Endogenous Comt Activity In Mouse Cytosolic Extractsmentioning

confidence: 99%

S-Adenosylmethionine-dependent Protein Methylation in Mammalian Cytosol via Tyrphostin Modification by Catechol-O-methyltransferase

Lipson

Clarke

2007

Journal of Biological Chemistry

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“…Both chestanin and chesnatin contain the dehydrogallic acid structural fragment (50) ester-ified to a phenolic glycoside. Dehydrodigalloyl esters (50) can be visualised as being derived (Scheme 11) by CoO as opposed to C-C oxidative coupling of two galloyl ester groups; thus in the chestnut galls (Castanea crenata) chestanin (58) is probably derived by intermolecular oxidative coupling of the galloyl ester groups in two molecules of the galloyl glycoside precursor cretanin (59) (58) Perhaps the most interesting aspect of the chemistry of dehydrodigallic acid is the unusual fission of the diaryl ether linkage which takes place in aqueous alkali (Scheme 16) (39). The reaction may be formulated as a ~-elimination process.…”

Section: Mallotus Japonicusmentioning

confidence: 99%

The Metabolism of Gallic Acid and Hexahydroxydiphenic Acid in Higher Plants

Haslam

1982

Fortschritte Der Chemie Organischer Naturstoffe / Progress in the Chemistry of Organic Natural Products

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“…The substituted 1,2-benzenediols required were synthesized by known methods and are listed in Table . The phenoxy-substituted 1,2-benzenediols 22-27 were prepared by Ullmann reaction, followed by ether cleavage as shown in Scheme , by a procedure described by Mayer and coworkers. 20 The phenylalkyl-, phenylcycloalkyl-, and in- danyl-substituted 1,2-benzenediols 28-40 were prepared by HaSOvcatalyzed Friedel-Crafts reaction in refluxing toluene (Scheme ) by the procedure described by Buu-Hoi and coworkers.21 Yields are given in Table . Reaction of 1,2-benzenediol with either 2-methyl-l-phenyl-l-propene (XI, X, R = H; R', R" = Me) or 2-methyl-3-phenyl-lpropene (XII) gave a 1:1 mixture of the two possible addition products 35 and 36 that cocrystallized, as described in the Experimental Section. Biological Evaluation.…”

Section: >-Cookmentioning

confidence: 99%

Hypolipidemic substituted 1,3-benzodioxole-2-carboxylates

Jm¹,

Gp²,

Ra³

et al. 1974

J. Med. Chem.

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Über eine ungewöhnliche Spaltung von Diaryl‐äthern

Cited by 13 publications

References 14 publications

S-Adenosylmethionine-dependent Protein Methylation in Mammalian Cytosol via Tyrphostin Modification by Catechol-O-methyltransferase

S-Adenosylmethionine-dependent Protein Methylation in Mammalian Cytosol via Tyrphostin Modification by Catechol-O-methyltransferase

The Metabolism of Gallic Acid and Hexahydroxydiphenic Acid in Higher Plants

Hypolipidemic substituted 1,3-benzodioxole-2-carboxylates

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