Of L-omithine

Rees, C.J., Op ng, K., Al-Mardini, H., Hudson, M., Record, C.O. Effect of L-omithine-L-aspartate on patients with and without TIPS undergoing glutamine challenge a double blind, placebo controlled trial. Gut 2000 47 571-574... 

Kircheis G, Nilius R, Held C, et al. Therapeutic efficacy of L-omithine L-aspartate infusions in patients with cirrhosis and hepatic encephalopathy Results of a placebo-controlled, double-bUnd study. Hepatology 1997 25 1351-1360. 

A phytotoxin from cultures of Pseudomonas syringae pv.p/wseo/ico/a C15H34N9O8PS, Mr 531.52. In infected bean plants P. leads to chlorosis and accumulation of L-omithine. The reason for this is the irreversible inhibition of ornithine carbamoyltransferase (OCT), which converts ornithine to citrulline. P. is enzymatically degraded by the plant to octiddin (C5H15N4O4PS, Mr 290.24), which has a ca. 20-fold stronger inhibitory effect on OCT and thus accelerates the damage. Lit. Tetrahedron Lett. 25. 3931 (1984). - [CAS62249 77-8 (P.) 93289-64-6 (octiddin)]... 

Ammonia metabolism within the muscle may be improved by the administration of L-omithine-L- aspartate (LOLA). Controlled trials suggest that enteral and parenteral formulations of ornithine aspartate significantly reduce blood ammonia levels and have useful therapeutic effects in patients with cirrhosis and encephalopathy (Kircheis et al., 1997 Stauch et al., 1998). Poo et al. (2006) recently showed in a randomized, lactulose-controlled study of oral ornithine-aspartate in 20 patients with clinically overt HE that LOLA in contrast to lactulose significantly improved parameters of mental status, number connection test scores, asterixis scores and EEG. Both lactulose and LOLA reduced serum ammonia levels and improved quaUty of life scores. Since only 20 patients were included in this study the results cannot be considered proof for the superiority of LOLA compared to lactulose, while the data underscore the effect of both agents. Ornithine aspartate is well tolerated in general. From a theoretical point of view the combination of disaccharides and ornithine aspartate may be useful in patients with insufficient efficacy of only one of the two drugs. 

Kircheis, G., Nihus, R., Held, C., Bemdt, H., Buchner, M., Gbrtelmeyer, R., Hendricks, R., Kruger, B., KuMinski, B., Meister, H., Otto, H.J., Rink, C., Rosch, W., Stanch, S. 1997. Therapeutic efficacy of L-Omithine-L-Aspartate infusions in patients With cirrhosis and hepatic encephalopathy Results of a placebo-controlled, double-blind study. Hepatology 25 1351-1360... 

L-lysine is a- e-diaminocarbon acid, the homologue of L-omithine, contains with one methylene group more than that. 

The biosynthesis of the piperidine-type nicotinoid anabasine proceeds in an analogous manner to nicotine, with A -piperideine (instead of the A-methyl-A -pyrrolinium cation) as the counterpart of nicotinic acid/3,6-dihydronicotinic acid (Leete 1969). Consequently, L-lysine is the source of the piperidine ring instead of L-omithine (Solt et al. 1960). Unlike the conversion of the latter to the N-methyl-A -pyrrolinium cation via free putrescine, the conversion of lysine to A -piperideine is assumed to proceed via a bound cadaverine (Friesen et al. 1992). 

N-DNP-v-omithine Hydrochloride. A sample of L-omithine hydrochloride (1.68 g, 10 mmoles) is dissolved in 15 ml of boiling water, and 2 g of CuCOa are added with stirring over a period of 10 min. The excess of CuCOs is removed by filtration and, after washing with 5 ml of hot water, the filtrate is collected. To the blue filtrate is added an excess of NaHCOs and a solution of 3.6 g of 2,4-fluoradinitrobenzene in 20 ml of ethanol. The reaction mixture is stirred for 2 hr at room temperature. The green precipitate formed is filtered, washed successively with water, ethanol, and ether, and then dissolved in 10 ml of 3 N HCl. After about 10 min a yellow precipitate is formed, which is collected and washed sequentially with 5 ml of cold 3 N HCl, 5 ml of cold water, ethanol, and ether. Yield, 2.35 g (70%) m.p. 258°. 

The two most common betaines found in plants, glycine betaine and trigonelline, have no asymmetric carbon atom. The betaine of tryptophan, hypaphorine, has only been found in the l form. Ackermann (1913a,b) isolated from meat extract a base which was possibly hexa-methylomithine and whose rotation was found to be opposite to that of the betaine of L-omithine however, the structure of this substance has never been satisfactorily established. The betaine of proline, stachy-drine, was first isolated from Stachys roots and orange leaves in the... 

FIGURE 11.1 Recent examples of L-omithine- and L-lysine-derived alkaloids, which involve the Mannich reaction as key step in the total synthesis toward these alkaloids. 

Singh, R., Pervin, S., and Chaudhuri, G. (2002). Caspase-8-mediated BID cleavage and release of mitochondrial cytochrome c during Nomega-hydroxy-L-arginine-induced apoptosis in MDA-MB-468 cells. Antagonistic effects of L-omithine. J. Biol. Chem. 277(40), 37630-37636. 

Many kinds of amino acids (eg, L-lysine, L-omithine, t-phenylalanine, L-threonine, L-tyrosine, L-valine) are accumulated by auxotrophic mutant strains (which are altered to require some growth factors such as vitamins and amino acids) (Table 6, Primary mutation) (22). In these mutants, the formation of regulatory effector(s) on the amino acid biosynthesis is genetically blocked and the concentration of the effector(s) is kept low enough to release the regulation and iaduce the overproduction of the corresponding amino acid and its accumulation outside the cells (22). 

Uchegbu and coworkers have studied the complexation and delivery of DNA using a unique poly(amino acid)-based polymer vesicle. A polymer of either poly (L-lysine) or poly(L-omithine) was functionalized with methoxy-poly(ethylene glycol) (mPEG) and hydrophobic palmitic acid chains to synthesize an amphiphilic triblock of either mPEG-6-poly(L-lysine)-6-palmitoyl or mPEG-Z>-poly(L-omithine)-6-palmitoyl. Vesicles formed from these polymers were complexed with DNA and showed improved transfection in vitro over poly(amino acid) complexed with DNA or DNA alone [82]. 

The polarographic method has been used to determine the stability constants and kinetic parameters of ternary complexes of Zn(II) with L-lysine, L-omithine, L-serine, L-phenylglycine, L-phenylalanine, L-glutamic acid, and L-aspartic acid as primary ligands and picoline as secondary ligand at pH 8.5 [103] and also of zinc complexation by extracellular polymers extracted from activated sludge [104]. 

The life cycle of Dictyostelium discoideum is described briefly in Box 11-C. About 105 individual amebas aggregate to form a moving "slug" in response to the chemoattractant cAMP. Some other species of Dictyostelium are attracted to a folic acid derivative or to the ethyl ester of N-propionyl-y-L-glutamyl-L-omithine-5-lactam 226... 

Satake, I. and Yang, J.T. (1976) Interaction of sodium decyl sulfate with poly(L-omithine) and poly(L-lysine) in aqueous solution. Biopolymers, 15, 2263-2275. 

Cationic polymer is also frequently examined to increase the potential of a gene drug. Large molecular weight cationic polymers can condense pDNA more efficiently than cationic liposomes. They include poly-L-lysine (PLL), poly-L-omithine, polyethyleneimine (PEI), chitosan, starburst dendrimer and various novel synthetic polymers. These polymers can enhance the cellular uptake of pDNA by nonspecific adsorptive endocytosis. 

N-alkylation via nucleophilic attack of amine on to imine the other product is L-omithine... 

Similar photosolubility effects have been observed for azo-modified poly(L-omithine) [Scheme 5, VIII (n = 3) 139 and poly(L-a, 3-diaminopropanoic acid) [Scheme 5, VIII (n = 1), 142 monitoring transmittance at 650 nm as a function of irradiation time. The initially turbid samples in HFP/water became dear upon irradiation at 360 nm as a consequence of the trans—>ds isomerization. On new irradiation at 460 nm, the clear solutions became turbid once more as a consequence of the reverse cis/trans isomerization of the azo chromophores. 

The assay developed for this activity involves the reaction of the P5C with o-aminobenzaldehyde (OAB) to form the reaction product dihydroquinozoli-nium (DHQ). The DHQ and unreacted OAB were separated by reversed-phase HPLC (LiChrosorb C18). The column was eluted isocratically with a mobile phase of 1 part methanol to 2 parts water, and the separation shown in Figure 9.37 obtained. The reaction mixture contained L-omithine (35 mAf), a-ketoglutarate, potassium phosphate (pH 7.4), and pryidoxyl phosphate in a total volume of 2 mL. The reaction was started by the addition of the homogenate and terminated by the addition of 1 mL of 3 N HO containing the OAB. Precipitated protein was removed by centrifugation (3000 rpm), and samples of the supernatant solution (10 nL) were injected for analysis. 

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