However, at higher 5,6-dihydrouracil concentrations that were comparable to those found in patients with a dihydropyrimidinase
deficiency, we obtained excellent reproducibility and recoveries for urine, urine-soaked filter paper strips, and plasma.
Dihydropyrimidinase deficiency: confirmation of the enzyme defect in dihydropyrimidinuria.
Dihydropyrimidinase deficiency: structural organization, chromosomal localization, and mutation analysis of the human dihydropyrimidinase gene.
After incubation of a homogenate of human lymphocytes with radiolabeled thymine, only 5,6-dihydrothymine could be detected, demonstrating the absence of detectable dihydropyrimidinase and [beta]-ureidopropionase activity (Fig.
14]C]Thymine was catabolized by human liver to radiolabeled dihydrothymine, N-carbamyl-[beta]-aminoisobutyric acid, and [beta]-aminoisobutyric acid, showing the presence of all three active enzymes--DPD, dihydropyrimidinase, and [beta]-ureidopropionase--of the catabolic pathway of the pyrimidine bases.
The absence of 3-ureidopropionic acid in the urine spectra of the patients with dihydropyrimidinase deficiency excluded the theoretical possibility of [beta]-ureidopropionase deficiency.
Dihydropyrimidinase deficiency: a progressive neurological disorder?