Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.1.1.17 (ornithine decarboxylase)
 6,351 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Myocardial ornithine decarboxylase appears to have characteristics similar to those of enzymes isolated from other tissues. Ornithine decarboxylase activity decreased very rapidly after the death of the animal. Storage of the cell sap fraction at 0 degrees C or -15 degrees C, however, led to only a small decrease in the enzyme activity up to 3 days after preparation. Pyridoxal phosphate at an optimum of 50 muM was essential for full enzyme activity. Thiol compounds did not increase the myocardial ornithine decarboxylase enzyme activity. The subcellular distribution of the enzyme in the myocardium was found to be different from that reported in other tissues. A partial purification of the enzyme was possible using the proteins precipitated at pH 5 from a cell-soluble fraction or by passing a soluble fraction through a Sephadex G 100 gel column. ATP, ADP, and AMP inhibited ornithine decarboxylase at high concentrations (5 mM), but GTP, CTP, and ITP inhibited at a 1 mM concentration and above.
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PMID:Some properties of rat myocardial ornithine decarboxylase and the in vitro effects of nucleotides. 0 62

It is shown that most ornithine in a chicken liver homogenate is decarboxylated in the particulate fraction. This fraction, however, requires the cytosol for complete activity. The dialyzed supernatant does not activate decarboxylation of ornithine, while the supernatant is more effective when previously inactivated at 100 degrees C. The supernatant can be substituted by the intermediates of the citric acid cycle (oxaloacetate, citrate, succinate, malate), by pyruvate, and partially by ADP as well. Rotenone blocks decarboxylation suggesting that this occurs through the pathway ornithine leads to glutamic semialdehyde leads to glutamate leads to alpha-ketoglutarate, which in turn is decarboxylated. The activating metabolites would thus have a role in reoxidizing NADH, and the ketoacids also in supplying the acceptor for transamination of glutamate, and indirectly for ornithine transamination. Pyruvate and oxaloacetate do not transaminate with ornithine. Insulin promotes a marked increase of cytosol ornithine decarboxylase activity, but has little effect on decarboxylation by the particulate cellular fraction.
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PMID:Catabolism of ornithine in chicken liver. 55 76

Rat thyroid cells in culture (FRTL-5 strain) require thyrotropic hormone (TSH) for growth. TSH alone in serum free medium is able to induce DNA synthesis of FRTL-5 cells. DNA synthesis occurs 18-20 hours following TSH stimulation of quiescent cells. Here we demonstrate that two sets of genes, related to the entry of cells in the S phase, are induced by TSH: 1) immediate early genes, such as c-jun and a gene coding for a zinc-finger protein Xrox 20/Egr2, both having a pattern of expression similar to the c-fos oncogene; 2) early delayed genes such as ornithine decarboxylase (ODC), 2F-1, a gene that shows a strong similarity in aminoacid sequence to a mitochondrial ADP/ATP carrier, and the asparagine synthetase gene (TS11). Furthermore, an increased expression of the histone H3 gene, a typical marker of S phase, has been observed in TSH-treated FRTL-5 cells.
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PMID:TSH is able to induce cell cycle-related gene expression in rat thyroid cell. 154 96

In order to elucidate the role of polyamines in the replication and insulin production of insulin-secreting cells, we have investigated the impact of partial polyamine depletion on the proliferation, metabolism, insulin synthesis and ultrastructure of clonal rat insulinoma cells (RINm5F). For this purpose RINm5F cells were exposed for 4 days to the specific ornithine decarboxylase (ODC) inhibitor difluoromethylornithine (DFMO). This resulted in a profound decrease in ODC activity and cytoplasmic polyamine contents. The polyamine content of cell nuclei was, however, not altered by DFMO. Addition of small amounts of putrescine during culture elevated the intracellular content of this diamine and suppressed ODC activity. The decrease in polyamine contents was accompanied by a pronounced inhibition of the cellular proliferative activity. The rates of glucose utilization, oxygen uptake and activity of the pentose cycle were decreased in DFMO-treated cells, whereas the glucose oxidation rate, oxidation/utilization ratio, ATP content and ATP/ADP ratio were increased. Insulin mRNA content and synthesis of proinsulin, insulin and total protein were not altered by DFMO. In contrast, there was a sizeable increase in the cellular insulin content, despite a lowered total protein content. Electron-microscopic analysis revealed an accumulation of insulin-secretion granules in the DFMO-treated cells. In addition, short-term insulin release was increased after DFMO exposure, but was not rendered glucose-sensitive. It is concluded that polyamines are necessary for the maintenance of rapid insulinoma-cell replication and that DFMO-treated RINm5F cells acquire an enhanced substrate oxidation and increased content of insulin and ATP.
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PMID:Increased glucose oxidation and contents of insulin and ATP in polyamine-depleted rat insulinoma cells (RINm5F). 185 81

1. Relationships between ornithine decarboxylase (ODC) and adenosine diphosphate ribosyl transferase (ADPRT) in human mononuclear leukocytes (HML) were tested by statistical comparisons of their values in a group of 46 people, and by use of inhibitors of ADPRT. 2. ODC was assayed following exposure of HML, for 20 hr, to mitogens [phytohemagglutinin (PHA) and pokeweed mitogen]; ADPRT was measured following exposure of HML to H2O2 (100 microM) for 1 hr (activated ADPRT), and in parallel cultures without H2O2 (constitutive ADPRT). 3. Significant correlations were found between ODC and ADPRT values; the effects of smoking disturbed the correlations. PHA induction of ODC was negatively influenced by age (standardized beta coefficient = -2.95, P = 0.005), while age also influenced ADPRT values negatively in non-smokers (for H2O2 activated ADPRT, standardized beta coefficient = -2.74, P less than 0.008). 4. Inhibitors of ADPRT, nicotinamide, caffeine and benzamide inhibited the induction of ODC by PHA in a concentration-dependent manner, in the range (0.6-10 mM) known to inhibit ADPRT.
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PMID:Mitogenic induction of ornithine decarboxylase in human mononuclear leukocytes: relationships with adenosine diphosphate ribosyltransferase. 213 20

The expression of genes coding for the ATP/ADP translocase, calcyclin, ornithine decarboxylase, vimentin, proto-onc genes p53 and c-Ha-ras1 and also for two genes JE and KC with as yet unknown function was studied during regeneration of rat liver. Genes highly induced were: JE (2-8 h of regeneration), ATP/ADP translocase (8-18 h), c-Ha-ras-1 (6-48 h) and p53 (6-12 h). Vimentin and KC gene transcripts were not detectable in the first 48 h of liver regeneration, whereas ornithine decarboxylase and calcyclin gene transcripts were present at constant levels. Our findings extend the list of genes expressed at the early stages of liver regeneration.
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PMID:Expression of "cell-cycle-dependent" genes in regenerating rat liver. 245 62

In vivo effects of DL-alpha-difluoromethylornithine (DFMO) on the metabolism of polyamines and nucleotide phosphates were monitored in P388/S leukemia cells grown intraperitoneally in BDF1 inbred male mice. Inhibiting the ornithine decarboxylase (ODC) activity DFMO depleted putrescine and spermidine to 30-50 and 50-60%, respectively, and increased spermine to 25-60% compared with the controls, when given as 2% solution in drinking water of the tumor-bearing animals. DFMO treatment caused a parallel 56% elevation of total nucleotide content in tumor cells with distinct and significant increase of some nucleotide phosphates. The most pronounced alterations were shown in the intracellular UTP (202%), CTP (103%), ADP (92%) and ATP (71%) concentrations. Changes in polyamine and nucleotide phosphate metabolisms were dependent on tumor progression. A possible explanation of the metabolic events induced by DFMO is discussed.
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PMID:In vivo effects of DL-alpha-difluoromethylornithine on the polyamine and nucleotide phosphate metabolism in P388/S leukemia cells. 308 89

The effect of polyamine depletion on phosphorylation and ADP-ribosylation of low-Mr chromosomal proteins was studied in intact, mutant Chinese hamster ovary cells (CHO-P22) devoid of ornithine decarboxylase activity. When starved of polyamines for 6 days, severe polyamine deficiency develops and the cells gradually stop growing. The rate of DNA synthesis was retarded to 16% of the control value and to 29% in density-inhibited cells. The synthesis of high-mobility-group (HMG) proteins was decreased by 65% in polyamine-depleted cells and by 40% in density-inhibited cells. The synthesis of core histones was decreased by 40% both in polyamine-depleted and density-inhibited cells. In polyamine-depleted cells the molar ratio of the higher-Mr HMG proteins (HMG 1 + 2) to the lower-Mr HMG proteins (HMG 14 + P) was about one-half of that found in cells grown in the presence of putrescine or in density-inhibited cells. In contrast to HMG proteins, no major differences were found in the content of core histones in these cell populations. In the perchloric acid-soluble fraction of nuclear proteins, 32P was incorporated mainly into histone H1, HMG P and a protein migrating more slowly than HMG 1 (protein P1). Specific changes in the 32P-labeling and migration of a number of protein bands, including histone H1, was observed in polyamine-depleted cells as compared to cells grown in the presence of putrescine or to density-inhibited cells. ADP-ribosylation experiments using [3H]adenosine showed a different pattern of label distribution; the higher-Mr HMG proteins from polyamine-depleted cells contained about one-half the amount of label found in the proteins from control cells. The lower-Mr HMG proteins and histone H1 were the preferentially labeled proteins in polyamine-depleted cells. Labeling of core histones with [32P]orthophosphate or [3H]adenosine did not differ markedly in the two cell populations. The results obtained using intact polyamine auxotrophic cells indicated that polyamine depletion is connected with more severe alterations in amounts and covalent modifications (phosphorylation and ADP-ribosylation) of HMG chromosomal proteins and histone H1 than core histones.
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PMID:Alterations in amounts and covalent modifications of low-molecular-weight chromosomal proteins in Chinese hamster ovary cells during polyamine depletion. 358 Mar 72

The rapid activity modulation of ornithine decarboxylase (L-ornithine carboxy-lyase, EC 4.1.1.17) in Physarum polycephalum is closely correlated with a reversible post-translational modification of this enzyme. A factor has now been isolated from homogenates of exponentially-grown microplasmodia which catalyzes the conversion of the active enzyme form, A, into its less active, B state. Partial purification of this A-B converting factor has been achieved using DEAE-Sephacel chromatography and Ultrogel AcA-34 gel filtration. It appears to be a heat labile, acidic protein with a molecular weight of about 35 000 which binds to large macromolecules in crude fractions isolated using low ionic strength buffers. The in vitro converting reaction requires the presence of spermidine or spermine (1 mM) while putrescine is much less effective, and inorganic cations are ineffective at levels up to 5 mM. Enzyme conversion is reduced in elevated ionic strengths and in the presence of polyamine chelators such as ATP, ADP or GTP (1.0 mM). Under current assay conditions the interaction between ornithine decarboxylase and this factor is stoichiometric, yet it is not reversed even by conditions which favor dissociation of protein-protein interactions. This is the first report of the isolation of a protein factor which is involved in the interconversion of ornithine decarboxylase between its alternate enzyme states.
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PMID:Protein factor which induces conversion between Physarum ornithine decarboxylase forms in vitro. 721 46

Alkaline and acidic shifts in exponentially grown Escherichia coli cultures were accompanied by an abatement of the cell energetic status (decline of ATP and energy charge and increase of the ADP and AMP pools). This event led to a suspension of the growth at (the means of) pH 9.0 and 6.0 accordingly. An increment of ornithine decarboxylase activity and an efflux of putrescine from the cells were observed in the course of alkaline shift. Environmental acidification was accompanied by intensification of the cell respiration rate and H+ATPase activity in the absence of the putrescine efflux from the cells. The involvement of the polyamine synthesizing system in the regulation of cell K+ content and the role of the primary proton pumps in the maintenance of pH homeostasis are discussed.
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PMID:[Role of the energy status and putrescine transport in the maintenance of the intracellular pH homeostasis in the course of alkaline and acidic shifts in Escherichia coli]. 850 12


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