Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

The activity of ornithine decarboxylase (ODC), the first and rate-limiting enzyme in the polyamine biosynthetic pathway, is dramatically increased in proliferating cells. In addition to transcriptional regulation of ODC, the present study shows that the enzyme is regulated at the translational level by putrescine and spermidine. ODC synthesis is inhibited by an increase and stimulated by a decrease in their cellular content. Spermidine is a more potent negative regulator than is putrescine. The effects of polyamines on ODC synthesis were not attributable to changes in the cellular content of ODC mRNA, thus demonstrating regulation at the translational level.
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PMID:Translational regulation of ornithine decarboxylase by polyamines. 374 73

Isolated rat lens was punctured with a needle at a single point in the equatorial region and was incubated at 37 degrees C. Spermidine/spermine N1-acetyltransferase activity was increased about 5-fold at 8 h after the puncture. Concomitantly, putrescine content in the lens increased markedly at 8-16 h after the puncture, while spermidine levels were slightly depressed. Pretreatment of the lens with actinomycin D or cycloheximide blocked the increases of spermidine/spermine N1-acetyltransferase activity and putrescine content. Ornithine decarboxylase, on the other hand, was not induced to a detectable degree by this stimulus and 5 mM difluoromethylornithine could not block the increase of putrescine content. Polyamine oxidase showed a relatively constant activity that was sufficient for the metabolism of newly formed N1-acetylspermidine. These results suggested that, in the punctured lens, the polyamine levels were regulated predominantly by the activity of spermidine/spermine N1-acetyltransferase, but not by the induction of ornithine decarboxylase.
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PMID:Induction of spermidine/spermine N1-acetyltransferase in needle-punctured rat lens as a model of traumatic cataract. 375 17

The role of polyamines in cartilage is not known: they may be somehow related to the mechanism of calcification. In epiphyseal cartilage from calf scapulas, they are more concentrated in the ossifying area, where calcification takes place, than in the resting region. Spermidine is present in greater amounts than spermine and putrescine. Since ornithine decarboxylase (EC 4.1.1.17) is measurable only in the resting region of the tissue, it is in this area that polyamine biosynthesis occurs, while they accumulate in the ossifying area. Immunohistochemical evidence is obtained that only in the ossifying zone is spermidine extracellular. It is at this level that the matrix is rearranged to become calcified, and proteoglycans are dissociated and partially removed. The effect of polyamines on solutions of proteoglycan subunits has been studied in vitro by following variations of turbidity and viscosity. While in the presence of putrescine the specific viscosity decreases to asymptotic values, in the presence of either 30 mM spermidine or 2.5-10 mM spermine, the decrement is more marked. At the same concentrations, increase of the turbidity of proteoglycan subunit solutions was observed. Only spermidine showed the capacity of displacing proteoglycan subunits from a column of Sepharose 4B-type II collagen: at 15 mM concentration, about 90% of proteoglycans were removed from the column. Alkaline phosphatase activity, which plays an important role in calcification, is enhanced by spermidine and spermine. These results obtained in vitro support the hypothesis that polyamines may be related to calcification of preosseous cartilage.
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PMID:A possible role for polyamines in cartilage in the mechanism of calcification. 394 74

Laparatomy of the rat dramatically induced hepatic ornithine decarboxylase that reached a peak 4 h after the operation. A similar pattern was shown by putrescine concentration. Spermidine was also enhanced, while spermine maintained unchanged. Administration to the animals of either isoproterenol or glucocorticoids (hydrocortisone or dexamethasone) also caused dramatic elevation of liver ornithine decarboxylase. The effect of isoproterenol, but not that of glucocorticoids, was prevented by previous treatment with propranolol. The beta-blockade was unable to prevent the effect of laparatomy on the liver enzyme. This was obtained instead, by depleting the endogenous catecholamines with either alpha-methyl-p-tyrosine or reserpine. Under these conditions, administration of glucocorticoids had no effect on the hepatic enzyme.
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PMID:Response of hepatic ornithine decarboxylase and polyamine concentration to surgical stress in the rat: evidence for a permissive effect of catecholamines on glucocorticoid action. 401 57

Spermidine biosynthesis was extremely low early in germination of Bacillus megaterium spores and the spermidine level remained constant. Rapid synthesis began after 130 min and thereafter accounted for the increase in spermidine level which began at this time. Biosynthesis was greatly (>84%) diminished by exogenous spermine or spermidine. Arginine and ornithine were both converted efficiently into spermidine, but arginine was the more immediate precursor as shown by isotope competition studies and by the absence of ornithine decarboxylase and the presence of arginine decarboxylase. Exogenous putrescine was not incorporated into spermidine, although it was taken up rapidly and degraded.
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PMID:Spermidine biosynthesis during germination and subsequent vegetative growth of Bacillus megaterium spores. 421 2

1. Castration of adult rats resulted in marked decreases in the amounts of putrescine, spermidine and spermine in the ventral prostate gland. Spermidine concentrations decline rapidly over the first 11 days after androgen withdrawal, reaching a value of only 12% of normal controls. Spermine concentrations diminish more slowly, reaching 24% of normal within 11 days. The spermidine/spermine molar ratio falls from 0.9 to 0.46 under these conditions. Putrescine concentrations decrease by 70% at 7 days after castration and then remain constant for some days. 2. After daily injections of testosterone propionate to rats castrated 7 days previously, prostatic spermidine and putrescine concentrations increase significantly within 24h; normal or even greater values are observed within 8 and 4 days respectively. In contrast, the spermine concentration does not increase until 5 days after commencement of androgen treatment. 3. The activities of two enzymes involved in polyamine biosynthesis (ornithine decarboxylase and a putrescine-activated S-adenosyl-l-methionine decarboxylase system) were greatly decreased soon after castration: after 7 days the respective values were 15% of normal for ornithine decarboxylase and 7% of normal for putrescine-dependent decarboxylation of S-adenosyl-l-methionine. Injection of testosterone propionate into animals castrated 7 days previously induced a rapid increase in both enzymic activities: ornithine decarboxylase was doubled in 6h, and increased three- to four-fold within 48h, whereas the putrescine-dependent decarboxylation of S-adenosyl-l-methionine doubled in 3h and increased tenfold within 48h of commencement of daily androgen treatments. 4. The activity of these enzyme systems was very low in the ventral prostates of hypophysectomized rats and was increased by administration of testosterone in a manner similar to that found in castrated rats. 5. Alterations in the activity of two ventral-prostate enzymes involved in ornithine production (arginase) and utilization (ornithine-2-oxoglutarate transaminase) that result from changes in the androgenic status of rats are described. 6. The findings presented suggest that the activities of ornithine decarboxylase and the putrescine-dependent S-adenosyl-l-methionine decarboxylase system, rather than ornithine concentrations, are rate-limiting for the formation of putrescine and polyamines in rat ventral prostate. 7. The relation of polyamines to androgen-induced prostatic growth is discussed with particular reference to the biosynthesis of proteins and nucleic acids.
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PMID:Concentrations of putrescine and polyamines and their enzymic synthesis during androgen-induced prostatic growth. 542 Sep 53

1. Concentrations of polyamines, amino acids, glycogen, nucleic acids and protein, and activities of ornithine decarboxylase and S-adenosylmethionine decarboxylase, were measured in livers from control, streptozotocin-diabetic and insulin-treated diabetic rats. 2. Total DNA per liver and protein per mg of DNA were unaffected by diabetes, whereas RNA per mg of DNA and glycogen per g of liver were decreased. Insulin treatment of diabetic rats induced both hypertrophy and hyperplasia, as indicated by an increase in all four of these constituents to or above control values. 3. Spermidine content was increased in the livers of diabetic rats, despite the decrease in RNA, but it was further increased by insulin treatment. Spermine content was decreased by diabetes, but was unchanged by insulin treatment. Thus the ratio spermidine/spermine in the adult diabetic rat was more typical of that seen in younger rats, whereas insulin treatment resulted in a ratio similar to that seen in rapidly growing tissues. 4. Ornithine decarboxylase activity was variable in the diabetic rat, showing a positive correlation with endogenous ornithine concentrations. This correlation was not seen in control or insulin-treated rats. Insulin caused a significant increase in ornithine decarboxylase activity relative to control or diabetic rats. 5. S-Adenosylmethionine decarboxylase activity was increased approx. 2-fold by diabetes and was not further affected by insulin. 6. Hepatic concentrations of the glucogenic amino acids, alanine, glutamine and glycine were decreased by diabetes. Their concentrations and that of glutamate were increased by injection of insulin. Concentrations of ornithine, proline, leucine, isoleucine and valine were increased in livers of diabetic rats and were decreased by insulin. Diabetes caused a decrease in hepatic concentration of serine, threonine, lysine and histidine. Insulin had no effect on serine, lysine and histidine, but caused a further fall in the concentration of threonine.
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PMID:Polyamine and amino acid content, and activity of polyamine-synthesizing decarboxylases, in liver of streptozotocin-induced diabetic and insulin-treated diabetic rats. 616 56

Alterations in ornithine decarboxylase (ODC) activity and in the polyamine and nucleic acid (RNA and DNA) concentrations were studied in P388 leukemia cells and in the host liver at different times after intraperitoneal inoculation of 5 X 10(6) tumor cells into BDF1 mice. ODC activity of leukemia cells had a maximum at day 5 after tumor transplantation. Cellular spermidine concentration declined significantly during the first 5 to 6 days. The RNA concentration of tumor cells changed parallel to that of spermidine. In the livers of ascites tumor-bearing mice ODC activity was 5- to 20-fold of control and had a maximum at days 5 to 6 after tumor cell inoculation. Spermidine concentration in the host liver increased, whereas spermine decreased gradually with tumor growth.
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PMID:Polyamine metabolism in P388 leukemia cells and in ascites tumor-bearing mice. 647 29

1. Direct or indirect inhibitors of l-ornithine decarboxylase (EC 4.1.1.17), structurally related or unrelated to l-ornithine, including dl-alpha-difluoromethylornithine, alpha-methylornithine and 1,3-diaminopropane, used alone or in combination, decreased polyamine concentrations in rat hepatoma tissue culture (HTC) cells and increased S-adenosyl-l-methionine decarboxylase activity (EC 4.1.1.50). 2. Comparison of the catalytic properties of S-adenosyl-l-methionine from cells with elevated and normal activities revealed no apparent modification of the catalytic site as judged by affinity for the substrate, stimulation by di- and tri-amines and inhibition by methylglyoxal bis-(guanylhydrazone). 3. Actinomycin D and cycloheximide, and RNA and a proteinsynthesis inhibitor respectively, blocked the increase of S-adenosyl-l-methionine decarboxylase activity elicited by alpha-difluoromethylornithine. In polyamine-depleted cells the apparent half-life of elevated S-adenosyl-l-methionine decarboxylase activity, determined by inhibition of protein synthesis, was 2.5-fold longer than in control cells. The present results suggest that elevation of S-adenosyl-l-methionine decarboxylase activity by alpha-difluoromethylornithine is due to stabilization of the enzyme. 4. Restoration of the normal intracellular putrescine content, by addition of putrescine to the medium of polyamine-deficient cells, transiently increased S-adenosyl-l-methionine decarboxylase activity. Thereafter, intracellular conversion of putrescine into spermidine was accompanied by inactivation of the enzyme at a rate that was similar to that found on addition of spermidine itself. No relationship between total intracellular spermine content and S-adenosyl-l-methionine decarboxylase activity could be established. 5. Addition of 1mm-1,3-diaminopropane to polyamine-deficient cells did not cause a decrease in the activity of S-adenosyl-l-methionine decarboxylase, whereas addition of 1,5-diaminopentane (cadaverine) did. 1,3-Diamino-N-(3-aminopropyl)propane did not accumulate in cells treated with alpha-difluoromethylornithine and 1,3-diaminopropane, whereas addition of 1,5-diaminopentane led to the accumulation of 1,5-diamino-N-(3-aminopropyl)pentane. 1,3-Diamino-N-(3-aminopropyl)propane (10mum) was as effective as spermidine in decreasing S-adenosyl-l-methionine decarboxylase activity. Thus effectiveness of a diamine in decreasing enzyme activity is related to its capability of being converted into a closely structurally related homologue of spermidine by spermidine synthase. 6. The spermidine site of action appears to be post-translational since (a) the spermidine-induced decrease of S-adenosyl-l-methionine activity was not prevented by actinomycin D and (b) spermidine in the presence of cycloheximide led to a synergistic inactivation of the enzyme with a decay rate that progressively approached control values. Altogether these results are indirect evidence for a strict negative control of S-adenosyl-l-methionine decarboxylase by spermidine and substantiate previous findings [Mamont, Duchesne, Grove & Tardif (1978) Exp. Cell Res.115, 387-393]. Spermidine appears to act on some processes involved in denaturation and/or degradation of the enzyme protein. Putrescine appears to decrease the rate of these processes. The physiological significance of the regulatory control of S-adenosyl-l-methionine decarboxylase is discussed.
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PMID:Indirect evidence for a strict negative control of S-adenosyl-L-methionine decarboxylase by spermidine in rat hepatoma cells. 679 4

In experimental studies of u.v.-skin-carcinogenesis u.v.-radiation is usually given in discrete amounts over a protracted period of time. Epidermal polyamine profiles were investigated in hairless mice after single and multiple exposures to ultraviolet-B (u.v.B). Hairless mice were irradiated with u.v.B from FS40 sunlamps and sacrificed after 1, 5, 10 or 20 days of daily irradiation with 0.9 kJ/sq m u.v.B at 6, 24 or 48 h after the final irradiation. Epidermis was analyzed for ornithine decarboxylase (ODC) activity, and for its putrescine, spermidine and spermine content. Skin biopsies were examined for histological changes. As previously reported epidermal ODC activity was induced 6 h after one irradiation with u.v.B and reached a maximum activity at approximately 24 h. In contrast after 5, 10 or 20 daily irradiations with u.v.B the epidermal ODC activity was maximal at approximately 6 h after the final irradiation and by 24 h had returned towards control levels. The magnitude of the ODC activity measured 6 h after irradiation increased with the number of irradiations. A similar pattern was seen with epidermal putrescine levels where a marked shift from a peak at approximately 24 h after one irradiation with u.v.B to a peak at approximately 6 h after 20 days of irradiation with u.v.B occurred. Spermidine levels increased as the number of u.v.B exposures was increased and spermine levels tended to decrease. The spermidine/spermine ratio increased most rapidly during the first 5 exposures, and remained elevated through to 20 days of daily irradiation. Chronic irradiation with u.v.B results in rapid induction of ODC activity and putrescine accumulation in the epidermis, events also elevated by chemical or viral transformation.
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PMID:Epidermal polyamine profiles after multiple exposures to ultraviolet radiation. 686 Dec 73


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