Ureidosuccinic acid

Lieberman 1, A Komberg (1954) Enzymatic synthesis and breakdown of a pyrimidine, orotic acid II. Dihydro-orotic acid, ureidosuccinic acid, and 5-carboxymethylhydantoin. J Biol Chem 207 911-924. 

Lacroute F (1971) Non-Mendelian mutation allowing ureidosuccinic acid uptake in yeast. J Bacteriol 106 519-522... 

Drillien, R., and Lacroute, F. (1972). Ureidosuccinic acid uptake in yeast and some aspects of its regulation./. Bacterid. 109, 203-208. 

The first step in pyrimidine biosynthesis is the reaction catalyzed by aspartic transcarbamylase, a reaction in which the carbamyl group of carbamyl phosphate is transferred to aspartic acid to yield ureidosuccinic acid. In E. coli, the end products of the pyrimidine pathways, UTP and especially CTP, inhibit the transcarbamylase. Pardee and his associate, who discovered this important event, established that the site of action in the transcarbamylase molecule of the inhibitor is different from the site of action of the substrate. 

The carbamyl phosphate is condensed with a molecule of aspartate giving ureidosuccinic acid, from which orotic acid is formed by cyclization and oxidation. In the presence of PRPP and a pyrophosphorylase this acid forms a ribotide and decarboxylation yields uridine monophosphate. The decarboxylation of the product of amination of orotidine phosphate gives cytidine monophosphate (Fig. 75). It can be seen that the pentose intermediate in pyrimidine nucleotide biosynthesis is PRPP, the same as for purine nucleotide biosynthesis. 

An interesting aspartic acid derivative, namely, ureidosuccinic acid 18,... 

Urea-formaldehyde resins, MA condensations, 515 Ureidosuccinic acid, synthesis route, 48 UV radiation, polymerization initiation, 239, 241, 248... 

Since the orotic acid required by Lactobacillus could be replaced partially by carbamylaspartic acid, the latter compound was investigated further as a possible pyrimidine precursor labeled carbamylaspartic acid was as effective as orotic acid in labeling the nucleic acid pyrimidines of this microorganism (339). If ureidosuccinic acid were formed from oxalacetate or aspartate, it would be possible to outline the formation of the pyrimi-... 

L- and DL-dihydro-orotic acid supported growth of Lactobacillus bulgaricus 09. The D-isomer alone is not only without activity, but is reported to reversibly inhibit the growth-promoting property exerted by ureidosuccinic or orotic acid [74, 91]. The dihydro-orotic acid prepared by fusion of maleic acid and urea [130] is inactive in bothi. bulgaricus (B [128] and an enzyme system [72, 131]. A comparison of the urea fusion product and that prepared by catalytic hydrogenation of orotic acid revealed that the former is actually fumarylurea [132]. 

Ureidosuccinate can be cyclized to form either a 5-membered or a 6-membered ring (III), and enzymes that carry out both of these reactions have been separated from an anaerobic bacterium grown on orotic acid. ... 

Even though orotidine has been implicated in the complex set of reactions leading to pyrimidine formation, the role of orotic acid per se must still be evaluated. On the one hand, it is possible that it is a normal intermediate which condenses with ribose to yield orotidine during pyrimidine synthesis. In contrast, an aliphatic acid, such as amino-fumaric i or ureidosuccinic, could conceivably couple with ribose and subsequently yield orotidine directly without the existence or participa-... 

The formation of carbamylaspartic acid from carbamyl phosphate and aspartic acid (Fig. 20) has been demonstrated in pigeon liver, several tissues of the rat, E. colt, and yeast (363S67). It appears that only one enz3rme was involved in thb interesting reaction 368) and it has been named ureidosuccinic (carbamylaspartic) acid synthetase 355). The reaction was essentially irreversible, even though slight reversal was shown with labeled substrates 357). 

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