Polyamine biosynthesis in rat prostate. Substrate and inhibitor properties of 7-deaza analogs of decarboxylated S-adenosylmethionine and 5'-methylthioadenosine

Coward, James K.; Motola, Nancy C.; Moyer, James D.

doi:10.1021/jm00214a008

Cited by 60 publications

(33 citation statements)

References 15 publications

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“…2, A-C). The effect of MTA on SAM/SAH was less pronounced than that of POA or ARS, consistent with MTA not directly inhibiting AHCY (26). Thus, the strength of the effect of MTA on SEPP1 secretion into cellconditioned media paralleled its quantitative effect on SAM/ SAH levels (Fig.…”

Section: Inhibition Of Ahcy Reduced Secretion Of Sepp1 Protein-tosupporting

confidence: 71%

S-Adenosylmethionine-dependent Protein Methylation Is Required for Expression of Selenoprotein P and Gluconeogenic Enzymes in HepG2 Human Hepatocytes

Jackson

Cao

Zeng

et al. 2012

Journal of Biological Chemistry

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Background: Protein methylation is required for gluconeogenic enzyme expression. Selenoprotein P is transcriptionally controlled similarly to gluconeogenenic enzymes. S-adenosylhomocysteine is an inhibitor of methylation. Results: S-Adenosylhomocysteine decreases selenoprotein P and gluconeogenic enzyme expression. Conclusion: Hepatocellular methylation is a nexus of control over selenoprotein P and gluconeogenic enzyme expression. Significance: Determination of how methylation affects proteins involved in type II diabetes may aid in development of therapeutics.

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Section: Inhibition Of Ahcy Reduced Secretion Of Sepp1 Protein-tosupporting

confidence: 71%

S-Adenosylmethionine-dependent Protein Methylation Is Required for Expression of Selenoprotein P and Gluconeogenic Enzymes in HepG2 Human Hepatocytes

Jackson

Cao

Zeng

et al. 2012

Journal of Biological Chemistry

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“…Conversely, the replacement ofthe adenine 6-amino group by a hydroxy group, as well as the replacement of N-7 of adenine by a methinic radical, resulted in an almost complete loss of activity. The resistance of 5'-methylthiotubercidin to enzymic hydrolysis has also been observed by Coward et al (1977) with the enzyme purified from rat prostate.…”

Section: Discussionmentioning

confidence: 89%

“…quenching for purine compounds, the ninhydrin reaction for amino acids and the iodoplatinate spray (Winegard & Toennies, 1948) for sulphur-containing compounds were used to detect 5'-methylthioadenosine and the analogues and derivatives. 5'-Methylthiotubercidin was a gift from Dr. J. K. Coward (Coward et al, 1977). Seleno-DL-methionine, reduced glutathione, reduced and oxidized dithiothreitol, iodoacetic acid, iodoacetamide and p-chloromercuribenzoic acid were supplied by Sigma Chemical Co., St. Louis, MO, U.S.A.…”

mentioning

confidence: 99%

Substrate specificity of 5′-methylthioadenosine phosphorylase from human prostate

Zappia¹,

Oliva²,

Cacciapuoti³

et al. 1978

Biochemical Journal

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5'-Methylthioadenosine phosphorylase was purified approx. 340-fold from human prostate by using affinity chromatography by Hg-coupled Sepharose. The enzyme, responsible for the breakdown of 5'-methylthioadenosine into adenine and methylthioribose 1-phosphate, was partially characterized. The apparent Km for 5'-methylthioadenosine is 25,uM. It is activated by thiols and shows an absolute requirement for phosphate ions. New analogues of 5'-methylthioadenosine were prepared and their activity as substrates or inhibitors of the reaction was investigated. The replacement of the 6-amino group of the adenine moiety by a hydroxy group, as well as the replacement of N-7 by a methinic radical, resulted in an almost complete loss ofactivity. Otherwise the replacement of sulphur by selenium, as well as that of the methyl group by an ethyl one, is compatible with the activity as substrate. The positively charged sulphonium group also prevents catalytic interaction with the enzyme. The inhibitory effect of 5'-methylthiotubercidin (competitive) and 5'-dimethylthioadenosine sulphonium salt (non-competitive) was also demonstrated. The reported results suggest three binding sites between the substrate and the enzyme.

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“…The apparent Km value for putrescine (between 25 and 250 Mm) at a fixed concentration of decarboxylated SAM (25 Mm) was about 32gM. The Km values for putrescine and decarboxylated SAM for spermidine synthases from other sources vary according to different workers (2,7,(14)(15)(16).…”

Section: Sindhu and Cohenmentioning

confidence: 99%

Propylamine Transferases in Chinese Cabbage Leaves

Sindhu¹,

Cohen²

1984

Plant Physiol.

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We have found spermidine synthase and spermine synthase activities in extracts of leaves of Chinese cabbage (Brassica pekinensis var. Pak Choy) and have developed an assay of the former in crude extracts. The method is based on the transfer of the propylamine moiety of decarboxylated S-adenosylmethionine to labeled putrescine, followed by ion-exchange separation of the labeled amine substrate and product, which are then converted to the 5-dimethylamino-1-napthalene sulfonyl (dansyl) derivatives and further purified and identified by thin layer chromatography. The specific radioactivity of putrescine present in the reaction mixture is determined, as is the radioactivity present in dansyl spermidine. The enzyme is also present in extracts of spinach leaves.Spermidine synthase has been purified about 160-fold from Chinese cabbage leaves. After partial purification, a rapid coupled enzymic assay has been used to study various properties of the enzyme. The plant enzyme shows maximum activity at pH 8.8 in glycine-NaOH buffer and has a molecular weight of 81,000. The Km values for decarboxylated Sadenosylmethionine and putrescine are 6.7 and 32 micromolar, respectively. The enzyme activity is inhibited strongly by dicyclohexylamine, cyclohexylamine, and S-adenosyl-3-thio-1, 8-diaminoctane. Of these, dicyclohexylamine is the most potent inhibitor with an Iso at 0.24 micromolar.Propylamine transferases, catalyzing the synthesis of spermidine from putrescine (spermidine synthase, EC 2.5.1.16) and of spermine from spermidine (spermine spermidine, EC 2.5.1.-), utilize decarboxylated SAM2 as the propylamine donor. Both the polyamine and MTA are formed in equivalent amounts. Spermidine synthase was first discovered in Escherichia coli (23) and was later purified and characterized from this source (2). Spermidine synthase and spermine synthase have been reported in several mammalian tissues (reviewed in 26) and are separable from SAM decarboxylase. With the aid of affinity chromatography, these enzymes have now been purified to homogeneity from rat ventral prostate and bovine brain and characterized (16,17).In (25), and a significant fraction of the triamine is found in a nonexchangeable association with the virus (5). Despite the advances with the bacterial and mammalian enzymes, there have been few studies on the enzymes ofspermidine and spermine synthesis in plants. Decarboxylated SAM, the propylamine donor, is not commercially available and has to be prepared either enzymically or synthesized chemically. Furthermore, the crude plant extracts are complex, which limit the choice of a suitable assay of the enzymes. Methods dependent on the isolation of labeled MTA from labeled decarboxylated SAM (10) could not be applied to the Chinese cabbage extracts because MTA was rapidly degraded. Coupled enzymic assays (2,22,27) are affected adversely by the presence of degradative enzymes. Bypassing these difficulties, we have developed an assay for spermidine synthase which is useful for crude extracts. After partial purifica...

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Polyamine biosynthesis in rat prostate. Substrate and inhibitor properties of 7-deaza analogs of decarboxylated S-adenosylmethionine and 5'-methylthioadenosine

Cited by 60 publications

References 15 publications

S-Adenosylmethionine-dependent Protein Methylation Is Required for Expression of Selenoprotein P and Gluconeogenic Enzymes in HepG2 Human Hepatocytes

S-Adenosylmethionine-dependent Protein Methylation Is Required for Expression of Selenoprotein P and Gluconeogenic Enzymes in HepG2 Human Hepatocytes

Substrate specificity of 5′-methylthioadenosine phosphorylase from human prostate

Propylamine Transferases in Chinese Cabbage Leaves

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