Disease relevance of Orotidine

• 2. The erythrocyte orotidine concentrations were much higher in patients with renal failure or with the Lesch-Nyhan syndrome [1].
• The increased orotidine excretion appears to be due to the use in the infants of higher allopurinol doses per kilogram of body weight than in the children [2].
• Comparative activity of erythrocyte adenosine deaminase and orotidine decarboxylase in Diamond-Blackfan anemia [3].
• Purifications and properties of orotidine-phosphorolyzing enzyme and purine nucleoside phosphorylase from Erwinia carotovora AJ 2992 [4].

High impact information on Orotidine

• We conclude that measurement of urinary orotidine excretion after the administration of allopurinol is a simple and reliable test for the identification of women who are heterozygous for ornithine carbamoyltransferase deficiency [5].
• OMPase was partially purified and is shown to cleave OMP to orotidine and inorganic phosphate [6].
• 4. A good correlation was found between urinary oxypurinol-7-riboside excretion and erythrocyte orotidine concentrations [1].
• Methyl donors are unable to overcome azacytidine-induced inhibition while pyrimidine nucleosides, except orotidine, can revert this inhibition totally [7].
• Simultaneous determination of plasma and urinary uric acid, xanthine, hypoxanthine, allopurinol, oxipurinol, orotic acid, orotidine and creatinine by high-performance liquid chromatography [8].

Biological context of Orotidine

• Density functional models of the mechanism for decarboxylation in orotidine decarboxylase [9].
• All four obligate heterozygotes showed orotic acid and orotidine excretion in excess of 3 S.D. above the control mean and a further 7 women had one or more excretion values in excess of 3 S.D., while 16 gave a value of less than 2 S.D. for both metabolites [10].

Anatomical context of Orotidine

• 6. Of the radioactive early intermediates which accumulated, only orotate, its derivatives (orotidine and orotidine 5'-monophosphate) or both appeared in the medium, presumably the result of leakage through the cell membranes [11].
• The concentration of orotic acid in the blood plasma of patients before hemodialysis exceeded 14 times its level in healthy subjects; the inhibition of uric acid synthesis by allopurinol in dialyzed patients was accompanied by enlargement of orotidine and orotate accumulation in blood plasma [12].

Associations of Orotidine with other chemical compounds

• We propose that erythrocyte orotidine formation results primarily from inhibition of orotidine-5'-monophosphate decarboxylase by oxypurinol-7-ribotide [1].
• The Michaelis constants for uridine and orotidine were 0.75 mM and 10.87 mM, respectively, at 40 degrees C. The PNPase of E. carotovora AJ 2992 had a molecular weight of 58,000 +/- 2,000 and seemed to be a dimer [4].
• Automated quantitative analysis for orotidine and uridine/thymine in urine by high-performance liquid chromatography with column switching [13].
• In the amplification step, Chinese hamster lung cells are selected for resistance to pyrazofurin and 6-azauridine, two inhibitors of the orotidine 5'-decarboxylase activity that converts OMP to UMP [14].

Gene context of Orotidine

• The specific activity of orotidine 5' monophosphate decarboxylase (coded by the URA3 gene) was 5 to 10 fold higher than in the wild type [15].
• Urinary excretion of orotic acid, orotidine and other pyrimidines in a patient with purine nucleoside phosphorylase deficiency [16].
• The method was used to measure orotic acid and orotidine in urine samples from newborns, healthy controls and patients with gout or deficiency of hypoxanthine-guanine phosphoribosyltransferase receiving allopurinol [17].

Analytical, diagnostic and therapeutic context of Orotidine

• Sequence analysis of the pyr-4 (orotidine 5'-P decarboxylase) gene of Neurospora crassa [18].
• Measurement of urinary orotidine and orotic acid after an oral allopurinol challenge is an important diagnostic test for ornithine carbamoyltransferase deficiency that is sometimes used in infants (< 1 year of age), although there is little information on normal test results in this age group [2].
• The identity of OMP and orotidine thus formed was confirmed by thin-layer chromatography [19].

References