Disease relevance of ornithine

• Cultured fibroblasts from a patient with gyrate atrophy of the retina do not convert L-ornithine, uniformly labeled with carbon-14, to proline [1].
• Two effectors of ornithine decarboxylase (ODC; L-ornithine carboxy-lyase, EC 4.1.1.17) have been extracted from an ODC- (speC-) mutant, Escherichia coli MA 255 [2].
• Kinetic analyses indicated that the papilloma OrnDCase has an altered affinity for its substrate, L-ornithine, compared to epidermal OrnDCase [3].
• Putrescine, the end-product of ornithine decarboxylase (ODC: L-ornithine carboxylyase, EC; 4.1.1.17) action, induces the synthesis of a protein(s), in L1210, neuroblastoma, and H-35 cells as well as in rat liver, which inhibits ODC activity [4].
• To test the hypothesis that ornithine decarboxylase (ODC; L-ornithine carboxy-lyase; EC 4.1.1.17) activity and polyamine concentrations change in response to acute hypoxia, we performed the following studies [5].

Psychiatry related information on ornithine

• An increase in L-ornithine decarboxylase activity that leads to a rapid increase in putrescine concentration appears to be essential during a critical period after implantation for continued mammalian embryonal growth [6].
• Increased immunostaining for L-ornithine decarboxylase occurs in neocortical neurons of Alzheimer's disease patients [7].
• With dietary restriction of protein intake and supplementary administration of L-ornithine and L-arginine, the high concentration of ammonia decreased and the clinical signs of truncal ataxia and lethargy improved [8].

High impact information on ornithine

• L-Ornithine decarboxylase:an essential role in early mammalian embryogenesis [6].
• The highly selective, enzyme-activated, irreversible inhibitor of L-ornithine decarboxylase, DL-alpha-difluoromethylornithine, suppresses the increase in uterine L-ornithine decarboxylase activity associated with early embryogenesis in the mouse and arrests embryonic development at that stage [6].
• We have investigated the dependence of Leishmania infection on arginase, which generates l-ornithine, in macrophages from BALB/c, C57BL/6, and nitric oxide synthase II (NOS II)-deficient mouse strains [9].
• However, exogenous l-ornithine almost completely inhibits parasite killing when added in the presence of LOHA to macrophages from NOS II-deficient mice or to BALB/c-infected cells activated with IFN-gamma plus LPS [9].
• Binding of L-ornithine, a product inhibitor, reveals a marked induced-fit mechanism, with a loop at the active site entrance changing its conformation accompanied by a shift of an alpha-helix by -4 A [10].

Chemical compound and disease context of ornithine

• Using strain MG1655 of Escherichia coli K-12 (F-, lambda-), we have determined the effects of polyamines and changes in growth rate on the transcription of several ribosomal genes and the polyamine-synthesizing enzymes ornithine decarboxylase (L-ornithine carboxy-lyase; EC 4.1.1.17) and arginine decarboxylase (L-arginine carboxylyase; EC 4.1.1.19) [11].
• Incubation of S49 lymphoma cells with N6,O2'-dibutyryl cyclic AMP (Bt2cAMP) decreases the activities of ornithine decarboxylase (L-ornithine carboxy-lyase; EC 4.1.1.17) and S-adenosylmethionine decarboxylase (S-adenosyl-L-methionine carboxy-lyase; EC 4.1.1.50), the two principal enzymes in the pathway of polyamine synthesis [12].
• Amino acid racemase of broad substrate specificity from Pseudomonas putida produced D- and L-glutamate from alpha-ketoglutarate through the transamination with L-ornithine [13].
• Replacement of L-ornithine in PT523 by L-2,4-diaminobutanoic acid or L-lysine did not decrease binding to human recombinant DHFR but resulted in some loss of activity against SCC25 human and SCC VII murine squamous cell carcinoma and against MCF-7 human breast carcinoma in culture [14].
• Intravitreal injection of L-ornithine hydrochloride in physiologic saline solution caused marked edema specifically in the pigment epithelium of Sprague-Dawley strain albino and Evans black hooded rats and rhesus and cynomologus monkeys [15].

Biological context of ornithine

• Cell proliferation is also restored by L-ornithine presumably due to in situ competitive inhibition of ornithine decarboxylase [16].
• L-Or-nithine N5-oxygenase catalyzes hydroxylation of L-ornithine, which is the first committed step of ferrichrome and ferrichrome A biosynthesis in U. maydis [17].
• This paper presents evidence that a polyamine-dependent protein kinase (EC 2.7.1.37) purified from nuclei of the slime mold Physarum polycephalum catalyzes phosphorylation of ornithine decarboxylase (OrnDCase; L-ornithine carboxy-lyase, EC 4.1.1.17) [18].
• The effect of 2',5'-oligoadenosine (trimer core) on cell growth, on erythrodifferentiation, and on the level of L-ornithine decarboxylase was tested [19].
• The enzyme exhibited normal Michaelia-Menten kinetics, and the apparent Michaelis constants for L-ornithine and carbamyl phosphate are 0.20 mM and 0.09 mM, respectively [20].

Anatomical context of ornithine

• Gyrate atrophy of the choroid and retina (GA) is an inherited chorioretinal degeneration caused by deficiency of ornithine delta-aminotransferase (OAT; L-ornithine: 2-oxo-acid aminotransferase; EC 2.6.1.13) [21].
• We used molecular cloning to isolate a functional gene for mouse ornithine decarboxylase (OrnDCase; L-ornithine carboxy-lyase, EC 4.1.1.17) from a cell line in which that gene had been selectively amplified [22].
• The synthesis and intracellular transport of the mitochondrial matrix enzymes ornithine transcarbamylase (carbamoylphosphate: L-ornithine carbamoyltransferase, EC 2.1.3.3.) and carbamoyl-phosphate synthetase (ammonia) I [carbon-dioxide:ammonia ligase (ADP-forming, carbamate-phosphorylating), EC 6.3.4.16] were studied in isolated rat hepatocytes [23].
• Nerve growth factor produces a rapid increase in the activity of ornithine decarboxylase (L-ornithine carboxy-lyase, EC 4.1.1.17) in superior cervical ganglia of young rats in vivo and in vitro [24].
• The cellular localization of the L-ornithine decarboxylase/polyamine system in normal and diseased central nervous systems [25].

Associations of ornithine with other chemical compounds

• Two-thirds of L-arginine consumption was due to macrophage arginase yielding L-ornithine and urea, which accumulated in medium [26].
• Arginase converts L-arginine to L-ornithine, which is the precursor of polyamines, which are essential components of cell proliferation [27].
• Treatment of SMC with PDGF stimulated DNA and putrescine synthesis, and this was enhanced further by increasing the extracellular concentration of L-ornithine [28].
• Two forms of ornithine decarboxylase (L-ornithine carboxy-lyase, EC 4.1.1.17) were purified from the livers of rats which had been treated with thioacetamide for 16 h (for details, see miniprint to Obenrader, M.F., and Prouty, W. F. (1977) J. Biol. Chem. 252, 2860-2865) [29].
• The P4XB2 strain, which is an arg R regulatory mutant, has a reduced lag effect in the presence of the tripeptide and appears to react to the intoxication by a further adjustment of the L-ornithine carbamoyltransferase cellular level [30].

Gene context of ornithine

• Ornithine decarboxylase (ODC), which metabolizes L-ornithine to polyamines, was also induced in H. pylori-stimulated macrophages [31].
• Moreover, inhibition of arginase reduces the number of parasites and delays disease outcome in BALB/c mice, while treatment with l-ornithine increases the susceptibility of C57BL/6 mice [32].
• In the kidney, L-ornithine is reabsorbed along the proximal convoluted tubule (PCT), transported by basolateral carriers, and produced by arginase II (AII) [33].
• An inhibitor of NO synthase, N5-iminoethyl L-ornithine (L-NIO), did not block the co-mitogenic effect of IL-1 beta, despite effective inhibition of NO synthase activity, suggesting that the synergistic interaction between IL-1 beta and FGF-2 was independent of the NO/cGMP pathway [34].
• Interaction between arginase and L-ornithine carbamoyltransferase in Saccharomyces cerevisiae. The regulatory sites of arginase [35].

Analytical, diagnostic and therapeutic context of ornithine

• Herein, the phoA promoter without its associated signal peptide is used to regulate expression of the HPRT of Schistosoma mansoni and the ornithine decarboxylase (ODC; L-ornithine carboxy-lyase, EC 4.1.1.17) of Trypanosoma brucei, two enzymes that have been identified as potential targets for antiparasitic chemotherapy [36].
• A ligand-exchange capillary electrophoresis was explored, with L-ornithine as the ligand and copper(II) as the central ion [37].
• Ornithine decarboxylase (L-ornithine carboxy-lyase, EC 4.1.1.17) has been purified from 3T3- and SV40-transformed 3T3 mouse fibroblasts by affinity chromatography, and the physicochemical properties of the two enzymes compared [38].
• After castration L-ornithine decarboxylase (ODC) and S-adenosyl-L-methionine decarboxylase (AMDC) activities fell in all tissues examined [39].
• We investigated the distribution of L-ornithine decarboxylase (ODC), an enzyme known to be involved in several developmental and restorative processes, in neocortical brain areas of Alzheimer's disease (AD) and normal patients by means of immunohistochemistry [7].

References