1/ + -Ornithine

M.p. 140°C. An amino-acid occasionally formed in the hydrolysis products of proteins and occurring in the urine of some birds as dibenzoylornithine. Ornithine is a precursor of arginine in plants, animals and bacteria. 

Ormdyl [96020-91-6] L-Ormthine [70-26-8] Ornithine [7006-33-9] Ormtrol Ornoprostol [70667-26-4] OROS... 

Ornithine-Derived Alkaloids. Ornithine (23) undergoes biological decarboxylation reductively to generate either putrescine [110-60-1] (36), or its biological equivalent, and subsequent oxidation and cyclization gives rise to the pyrroline [6724-81-2], (37), C H N. 

Lysine-Derived Alkaloids. Just as putresciae (36) derived from ornithine (23) is coasidered the pregenitor of the aucleus fouad ia pyrrolidine-containing alkaloids, so cadavetiae [462-94-2] (44), C H 4N2, derived from lysiae (24) is the idealized pregenitor of the 1-dehydropiperidine [28299-36-7] nucleus (45), C H N, found in the pomegranate, Sedum Dobelia, Dupin, and Lycopodium alkaloids (39). 

Tobacco Alkaloids. The relatively small number of alkaloids derived from nicotinic acid (27) (the tobacco alkaloids) are obtained from plants of significant commercial value and have been extensively studied. They are distinguished from the bases derived from ornithine (23) and, in particular, lysine (24), since the six-membered aromatic substituted pyridine nucleus common to these bases apparendy is not derived from (24). 

Manometric determiaation of L-lysiae, L-argioine, L-leuciae, L-ornithine, L-tyrosiae, L-histidine, L-glutamic acid, and L-aspartic acid has been reviewed (136). This method depends on the measurement of the carbon dioxide released by the T.-amino acid decarboxylase which is specific to each amino acid. 

AMP, ADP, and ATP = adenosine mono-, di-, and triphosphate IMP = inosine 5 -monophosphate AICAR = 5 -phosphoribosyl-5-amino-4-imida2olecarboxamide DAP = diaminopimelic acid PRPP = phosphoribosyl pyrophosphate a — KGA = a-ketoglutaric acid Orn = ornithine Cit = citnilline represents the one carbon unit lost to tetrahydrofolate as serine is converted to glycine. 

Likely impurity is ornithine. Crystd from water at pH 5-7, by adding EtOH to 80% (v/v). 

S-Citrulline (2>amino-5-ureidopentanoic acid) [372-75-8] M 175.2, m 222°, [o] +24.2° (in 5M HCl), pK 9.71. Likely impurities are arginine, and ornithine. Crystd from water by adding 5 volumes of EtOH. Also crystd from water by addn of MeOH. 

Hydroxy-L-lysine monohydrochloride [32685-69-1 ] M 198.7, [oi]q +17.8° (6M HCl), pKj 8.85, pK 9.83. Likely impurities are 5-a//o-hydroxy-(D and L)-lysine, histidine, lysine, ornithine. Crystd from water by adding 2-9 volumes of EtOH stepwise. 

Ornithine, proline, hydroxyproline, pipecolic acid and sarcosine yield red zones, glycine greenish-brown and the other amino acids weakly brown ones [3]. The colors of the zones are different if an alcoholic solution of potassium carbonate is used for basification instead of dipping solution II. 

This technique can be applied to prepare DL-a-fluoromethylputrescme (5-fluoropentane 1,4-diamine), a potent irreversible inhibitor of E colt ornithine decarboxylase, from 4-phthalimido-l -butyryl chloride, diazomethane, and hydro gen fluonde-pyridine [94 95]... 

A -Pyrroline has been prepared in low yield by oxidation of proline with sodium hypochlorite (71), persulfate (102), and periodate (103). A -Pyrroline and A -piperideine are products of enzymic oxidation via deamination of putrescine and cadaverine or ornithine and lysine, respectively (104,105). This process plays an important part in metabolism and in the biosynthesis of various heterocyclic compounds, especially of alkaloids. 

Certain amino acids and their derivatives, although not found in proteins, nonetheless are biochemically important. A few of the more notable examples are shown in Figure 4.5. y-Aminobutyric acid, or GABA, is produced by the decarboxylation of glutamic acid and is a potent neurotransmitter. Histamine, which is synthesized by decarboxylation of histidine, and serotonin, which is derived from tryptophan, similarly function as neurotransmitters and regulators. /3-Alanine is found in nature in the peptides carnosine and anserine and is a component of pantothenic acid (a vitamin), which is a part of coenzyme A. Epinephrine (also known as adrenaline), derived from tyrosine, is an important hormone. Penicillamine is a constituent of the penicillin antibiotics. Ornithine, betaine, homocysteine, and homoserine are important metabolic intermediates. Citrulline is the immediate precursor of arginine. 

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