One example of these markers is the URA3 gene that encodes orotidine
5-monophosphate decarboxylase (OMPD Case), an enzyme involved in the de novo synthesis of pyrimidine ribonucleotides (10).
5:1 and orotate, orotidine
and uridine-monophosphate (UMP) increase transiently before decreasing to levels approaching their original steady states (Kempt 1986).
In contrast, patients suffering from a urea-cycle disorder can, in addition to orotate, also excrete highly increased amounts of orotidine, uridine, and uracil (5, 7).
The IS mixture was prepared in water containing 1 mmol/L each of stable-isotope-labeled N-carbamyl-aspartate (N-C-aspartate), dihydroorotate, orotate, orotidine, uridine, and uracil.
Simple method of measurement of orotic acid and orotidine
To this effect, 340 clinical, veterinary, and environmental isolates from Argentina, Brazil, Chile, Colombia, Mexico, Peru, Venezuela, Guatemala, and Spain were typed by using M13 polymerase chain reaction-fingerprinting and orotidine monophosphate pyrophosphorylase (URA5) gene restriction fragment length polymorphsm analysis with Hhal and Sau961 in a double digest.
The molecular types were recently confirmed by RFLP analysis of the orotidine monophosphate pyrophosphorylase (URAS) gene and the phospholipase (PLB1) gene (19).
Determination of urine orotate and orotidine
and plasma ammonium.
2) reported increased allopurinol-induced excretion of orotidine in the urine in female carriers, which allowed diagnosis.
To clarify the best conditions for making these applications reliable, we studied several factors influencing the test results, such as protein intake, urine purification to eliminate analytical interferences, the determination of orotate or orotidine, and the use of cutoff values for interpretation.
Guanine was not detectable, whereas orotidine was clearly increased in both samples (112 and 63 [micro]mol/mmol creatinine).
In the urine of one patient while on allopurinol, the orotidine concentration was 30 [micro]mol/mmol creatinine.