Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: CAS:1069-31-4 (ornithine)
 6,755 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several vasopressin analogues were tested on pig kidney membranes for their ability to activate adenylate cyclase and to inhibit the binding of [8-lysine]vasopressin. Both the adenylate cyclase activation and hormonal binding were measured on the same enzyme preparation and under identical were measured on the same enzyme preparation and under identical experimental conditions. A preincubation period in the presence of hormone allowed the binding process to reach equilibrium. Peptide concentrations causing half-maximal adenylate cyclase activation (apparent Km) were, in the order of decreasing affinity:2.5 to 7.0 to 7.0 times 10-10 M [8-lysine] vasopressin, 3.1 to 4.0 times 10-9 M [8-arginine] vasopressin, 2.0 to 3.0 times 10-9 M [I,6-alpha-deaminocystathionine, 8-ornithine]vasopressin, 3.1 times 10-7 M des-9-glycineamide[8-lysine]vasopressin, 0.5 to 1.0 times 10-6 M[1,6-alpha-deaminocystathionine, 2-0-tert...
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PMID:Vasopressin-sensitive kidney adenylate cyclase. Structural requirements for attachment to the receptor and enzyme activation: studies with vasopressin analogues. 16 61

Six subjects from three sibships with hyperornithinemia, homocitrullinuria, and hyperammonemia are described. Assays of liver biopsy in one showed decreased CPS I and leukocyte assays indicate a similar defect in all six. Loading studies with ornithine and citrulline are consistent with a block early in the urea cycle between ornithine and citrulline. They thus support the results of the enzymatic assays. Similar studies with lysine and homocitrulline indicate there is excessive homocitrulline biosynthesis that is related to lysine intake, but there is no evidence of a block in the main lysine catabolic pathway. The younger more severely affected patients require protein restriction to 1.2 and 1.5 g/kg/24 hr to control hyperammonemia; hyperornithinemia remains unaffected. Adult subjects avoid large protein meals but tolerate a diet that is almost normal. The mode of inheritance of this disorder appears to be autosomal recessive. The fine structure of liver shows the presence of large and abnormally configurated mitochondria. There is a peculiar periodic structure situated closely to the inner mitochondrial membrane, and it is possible that the presence of this may be related to the impairment of transport of ornithine into the mitochondria; this in turn may give rise to hyperornithinemia. This disorder adds to the metabolic errors that suggest that there are close links of lysine metabolism to the urea cycle but the details are yet to be defined.
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PMID:Hyperornithinemia, hyperammonemia, and homocitrullinuria associated with decreased carbamyl phosphate synthetase I activity. 16 48

In the direction of reductive condensation of alpha-ketoglutarate and lysine, saccharopine dehydrogenase (N6-(glutar-2-yl)-L-lysine:NAD oxidoreductase (lysine-forming) is inhibited by high concentrations of alpha-ketoglutarate and lysine, but not by NADH. NAD+ and saccharopine show no substrate inhibition in the reverse direction. Substrate inhibition by alpha-ketoglutarate and lysine is linear uncompetitive versus NADH. However, when the inhibition is examined with alpha-ketoglutarate or lysine as the variable substrate, the double reciprocal plots show a family of curved lines concave up. The curvature is more pronounced with increasing concentrations of the inhibitory substrate, suggesting an interaction of variable substrate with the enzyme form carrying the inhibitory substrate. These inhibition patterns, the lack of interaction of structural analogs of lysine such as ornithine and norleucine with the E-NAD+ complex (Fujioka M., and Nakatani, Y. (1972) Eur. J. Biochem. 25, 301-307), the identity of values of inhibition constants of alpha-ketoglutarate and lysine obtained with either one as the substrate inhibitor, and the substrate inhibition data in the presence of a reaction product, NAD+, are consistent with the mechanism that substrate inhibition results from the formation of a dead-end E-NAD+-alpha-ketoglutarate complex followed by the addition of lysine to this abortive complex.
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PMID:Saccharopine dehydrogenase. Substrate inhibition studies. 17 2

We report the discovery of a functioning non-covalent complex between two peptides obtained from a limited tryptic digest of horse heart cytochrome c. We have used the phenomenon to produce three modified versions of the complex. We have replaced lysine-39 semisynthetically with ornithine in the first analogue, with p-fluorophenyl-alanine in the second, and removed it entirely in the third.
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PMID:A functioning complex between tryptic fragments of cytochrome c. A route to the production of semisynthetic analogues. 19 93

Proteus rettgeri has been found to contain two separable 1-amino acid oxidases. Both enzymes are particulate in nature, neither being ribosomal bound. One of these enzymes appears to have broad specificity, being active toward monoaminomonocarboxylic, imino, aromatic, sulfur-containing, and beta-hydroxyamino acids. The other enzyme has more limited specificity, catalyzing the oxidative deamination of the basic amino acids and citrulline. The affinity of this oxidase for the various substrates at pH 7.6 in decreasing order is arginine, histidine, ornithine, citrulline, and lysine. This enzyme has a particularly high affinity for arginine (Km equal to 0.27 mM), and anomalous kinetics are observed with increasing substrate concentrations. When concentrations of arginine greater than 1.0mM were added to the reaction containing histidine, imidazole pyruvate formation was completely inhibited.
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PMID:l-amino acid oxidases of Proteus rettgeri. 23 21

The chronically uremic rat has been used as a model to study amino acid metabolism in uremia. Uremic rats fed low protein diets (6% casein) survived longer than uremic rats receiving either higher levels of dietary protein or a low protein diet supplemented with a mixture of nonessential amino acids. Alterations in plasma amino acid levels were observed in the uremic rats and were similar to those found in patients with renal failure. Plasma concentrations of citrulline, free tryptophan, glycine and the methylhistidines were increased and levels of serine, ornithine, lysine, total tryptophan, tyrosine, and the tyrosine-phenylalanine ratio were reduced. The metabolic basis of the altered tyrosine-phenylalanine ratio in plasma was studied. Tyrosine aminotransferase (TAT) and phenylalanine hydroxylase (PHL) activity were normal in the liver, but renal PHL activity of was decreased as compared to control rats. Tissue concentrations of citrulline were also found to be raised in liver and muscle of uremic rats. The activity of ornithine transcarbamoylase, was reduced in the liver and arginine synthetase activity was decreased in the kidneys of uremic rats. Thus elevated citrulline levels in uremic tissue appear to be caused by a decrease conversion of citrulline to arginine in the kidney. Preliminary studies of tryptophan metabolism in uremic rats have shown elevated brain levels of 5-hydroxyindoleacetic acid and increased hepatic tryptophan oxygenase activity. Increased plasma amine levels were associated with altered activities of monoamine oxidase and diamine oxidase in kidney and other tissues.
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PMID:Amino acid metabolism in the chronically uremic rat. 23 43

The carbodiimide-catalyzed conjugation of a 6700 molecular weight fragment of poly-L-lysine to radiolabeled human serum albumin or to horseradish peroxidase enhances the membrane transport of each protein into cultured mouse fibroblasts approximately 11- and 200-fold, respectively. At least 50% of the peroxidase activity remained after conjugation. Trypsinization and carbamylation of the two conjugates demonstrates that the enhancement of their cellular uptake is related to their poly-L-lysine content. Simple addition to the medium of comparable amounts of free poly-L-lysine has no effect on the transport of either native protein. Addition of poly-L-ornithine (molecular weight 200,000) at 3-30 microgram/ml, a condition known to cause enhancement of 125I-labeled human serum albumin uptake by mouse sarcoma cells, has no visible effect on the cellular uptake of native horseradish peroxidase. The intracellular localization of the enzyme-poly-L-lysine conjugate can be demonstrated cytochemically by either light or transmission electron microscopy. A concentration of conjugate that increases the uptake more than 200-fold does not cause any detectable morphological change suggestive of cell toxicity. Furthermore, because poly-L-lysine is an excellent substrate for intracellular proteolytic enzymes, it can be expected to be broken down and reutilized in the cell.
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PMID:Conjugation of poly-L-lysine to albumin and horseradish peroxidase: a novel method of enhancing the cellular uptake of proteins. 27 16

Arginine dramatically stimulates bioluminescence in the marine bacterium Beneckea harveyi growing in minimal media, an effect that is due to increases in both the synthesis and expression of luciferase. To elucidate the mechanism of this phenomenon, studies were made of the transport and metabolism of arginine in B. harveyi. The transport of arginine and lysine involves two kinetically distinct transport systems for the uptake of arginine and lysine. In contrast, ornithine is transported only by a system common to all three amino acids. The internal amino acid pools were measured in mutants that do not show stimulation of bioluminescence by arginine and in wild-type cells that do. In minimal media, the internal arginine pools are undetectably low. Furthermore, exogenously added labeled arginine is rapidly transported and converted to citrulline and argininosuccinate. The results can be accommodated by a model in which the internal arginine is poised at a very low concentration; the stimulatory effect of exogenous arginine on luciferase biosynthesis occurs at the transcriptional level, and the actual mediator can be either arginine or argininyl transfer ribonucleic acid.
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PMID:Poising of the arginine pool and control of bioluminescence in Beneckea harveyi. 31 6

Head-space gas-liquid chromatography and mass spectrometry were used to detect and identify products formed by Proteus vulgaris, P. mirabilis, P. morganii, and P. rettgeri from a defined medium supplemented with either phenylalanine, methionine, valine, leucine, histidine, lysine, ornithine, threonine, asparagine, aspartic acid, or tryptophan. In a detailed study of the products formed by 68 strains of Proteus spp. from L-methionine, the production of large amounts of both dimethyl disulfide and methyl mercaptan was found to be a characteristic of the genus. Both sulfur products appeared within a few hours of inoculation. Dimethyl disulfide was a more sensitive indicator of growth than the spectrometric determination of optical density. This suggests that it could be useful for the rapid, automated detection of any species of Proteus.
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PMID:Methyl mercaptan and dimethyl disulfide production from methionine by Proteus species detected by head-space gas-liquid chromatography. 33 5

The general amino acid transport system of Saccharomyces cerevisiae functions in the uptake of neutral, basic, and acidic amino acids. The amino acid analogue N-delta-chloroacetyl-L-ornithine (NCAO) has been tested as potential site specific reagent for this system. L-Tryptophan, which is transported exclusively by the general transport system, was used as a substrate. In the presence of glucose as an energy source, NCAO inhibited tryptophan transport competitively (Ki = 80 micrometer) during short time intervals (1-2 min), but adding 100 micrometer NCAO to a yeast cell suspension resulted in a time-dependent activation of tryptophan transport during the first 15 min of treatment. Following the activation a time-dependent decay of tryptophan transport activity occurred. Approximately 80% inactivation of the system was observed after 90 min. When a yeast cell suspension was treated with NCAO in the absence of an energy source, an 80% inactivation of tryptophan transport occurred in 90 min. The inactivation was noncompetitive (Ki congruent to 60 micrometer) and could not be reversed by the removal of the NCAO. Addition of a five-fold excess of L-lysine during NCAO treatment or prevented inactivation of tryptophan transport. Under parallel conditions of incubation, other closely related transport systems were not inhibited by NCAO.
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PMID:Possible site-specific reagent for the general amino acid transport system of Saccharomyces cerevisiae. 33 48


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