• Title/Summary/Keyword: S-adenosylmethionine decarboxylase

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Studies on the active site of the Arabidopsis thaliana S-Adenosylmethionine Decarboxylase: $Lys^{81}$ residue involvement in catalytic activity

  • Park, Sung-Joon;Cho, Young-Dong
    • BMB Reports
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    • v.33 no.1
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    • pp.69-74
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    • 2000

  • The Arabidopsis thaliana S-Adenosylmethionine decarboxylase (AdoMetDC) cDNA ($GenBank^{TM}$ U63633) was cloned, then the AdoMetDC protein was expressed and purified. The purified AdoMetDC was inactivated by salicylaldehyde in a pseudo first- order kinetics. The secondorder rate constant for inactivation was 126 $M^{-1}min^{-1}$ with the slope of n=0.73, suggesting that inactivation is the result of the reaction of one lysine residue in the active site of AdoMetDC. Site-specific mutagenesis was performed on the AdoMetDC to introduce mutations in conserved $lysine^{81}$ residues. These were chosen by examination of the conserved sequence and proved to be involved in enzymatic activity by chemical modification. Changing $Lys^{81}$ to alanine showed an altered optimal pH. The substrate also provided protection against inactivation by salicylaldehyde. Considering these results, we suggest that the $lysine^{81}$ residue may be involved in catalytic activity.

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Effects of Agmatine on Polyamine Metabolism and the Growth of Prostate Tumor Cells

  • Choi, Yon-Sik;Cho, Young-Dong
    • BMB Reports
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    • v.32 no.2
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    • pp.173-180
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    • 1999

  • The effects of agmatine on the enzymes responsible for the biosynthesis of polyamines, the resultant levels of polyamines, and their effect on the growth of DU145 human prostate tumor cells were investigated. When agmatine was added to the medium, ornithine decarboxylase (ODC, EC 4.1.1.17) activity was substantially reduced, but S-adenosylmethionine decarboxylase (SAMDC, EC 4.1.1.50) activity increased markedly. These changes in ODC and SAMDC activities were the result of an induction of ODC-antizyme and a decreased turnover rate of SAMDC in the presence of agmatine. Accordingly, there was a decrease in the intracellular levels of putrescine and spermidine but an increase in the intracellular level of spermine. Cell growth was markedly inhibited by agmatine treatment and this inhibition was not recovered by the addition of putrescine or spermidine. Our results suggest that agmatine alters the intracellular amounts of polyamine in the cells, closely related to the inhibition of cell growth.

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Adenovirus-mediated Expression of Both Antisense Ornithine Decarboxylase and S-adenosylmethionine Decarboxylase Induces G1 Arrest in HT-29 Cells

  • Gong, Lei;Jiang, Chunying;Zhang, Bing;Hu, Haiyan;Wang, Wei;Liu, Xianxi
    • BMB Reports
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    • v.39 no.6
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    • pp.730-736
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    • 2006

  • To evaluated the effect of recombinant adenovirus Ad-ODC-AdoMetDCas which can simultaneously express both antisense ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (AdoMetDC) on cell cycle distribution in colorectal cancer cell and investigated underlying regulatory responses, human colorectal cancer cells HT-29 were cultured in RPMI 1640 medium and infected with Ad-ODC-AdoMetDCas. Cell cycle progression was detected by flow cytometry analysis. The expression levels of cell cycle regulated proteins were measured by Western blot analysis. The mRNA level of cyclin D1 was measured by RT-PCR. And a luciferase reporter plasmid of cyclin D1 promoter was constructed to observe the effect of Ad-ODC-AdoMetDCas on cyclin D1 promoter activity. The results showed that recombinant adenovirus Ad-ODC-AdoMetDCas significantly induced $G_1$ arrest, decreased levels of cyclin D1 protein and mRNA and suppressed the promoter activity. Ad-ODC-AdoMetDCas also inhibited nuclear translocation of $\beta$-catenin. In conclusion, downregulation of ODC and AdoMetDC mediated by Ad-ODC-AdoMetDCas transfection induces $G_1$ arrest in HT-29 cells and the arrest was associated with suppression of cyclin D1 expression and inhibition of $\beta$-catenin nuclear translocation. As a new anticancer reagent, the recombinant adenovirus Ad-ODC-AdoMetDCas holds promising hope for the therapy of colorectal cancers.

  • https://doi.org/10.5483/BMBRep.2006.39.6.730 인용 PDF

인삼(Panax ginseng C.A. Meyer) Saponin 성분이 흰쥐의 장기에서 Polyamine 대사에 미치는 영향

  • 최연식;조영동
    • Journal of Ginseng Research
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    • v.20 no.3
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    • pp.233-240
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    • 1996

  • In order to study effects of Korean ginseng (Panax ginseng C.A. Meyer) saponin fraction on polyamine metabolism in rat organs, Korean ginseng saponin fraction was administrated to rats for 1, 2, 3, 4, 6 and 12 months and brain, liver, prostate, spleen and testis were removed from these rats. Two enzyme activities were measured from those organs; ornithine decarboxylase (ODC), which is a regulatory enzyme of putrescence biosynthesis and S-adenosylmethionine decarboxylase (SAMDC), which is also a regulatory enzyme of spermidine and spermine biosynthesis. The amounts of polyamine were also determined. As for prostate and testis organs, Korean ginseng saponin fraction was innocuous for ODC and SAMDC activities from rats fed for 1 and 2 months. However, after 3 months, the stimulatory effect on the activities of two enzyme gradually increased in test groups and reached its maximum in 12 months. The contents of spermidine and spermlne of test groups in prostate and testis were also much higher than those of control groups. Another stimulatory effect on the activities of two enzymes was observed in liver and reached its maximum in 6 months. In the other organs such as brain and spleen, the enzymes were turned out to be not affected by feeding Korean ginseng saponin fraction. From the cumulative results, the stimulatory effect of Korean ginseng saponin fraction on polyamine metabolism was observed in prostate, testis and liver.

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