Simple Method for the Quantitative Analysis of Dihydropyrimidines and N-Carbamyl-ß-Amino Acids in Urine

Abstract

In man pyrimidines are degraded in four steps catalysed by dihydropyrimidine dehydrogenase (DHPD, EC 1. 3. 1. 2.), dihydropyrimidinase (DHP, EC 3. 5. 2. 2.), ureidopropionase (UP, EC 3. 5. 1. 6.) and a transaminase (Fig. 1). As yet only deficiencies of the first and the last enzymes have been described. Deficiency of R-ß-aminoisobutyrate aminotransferase (EC 2. 6. 1. 22.) is easily detected by classical amino acid analysis ¹’²,DHPD-deficiency by TLC or HPLC of pyrimidines in urine³. A method is presented for the detection of the two other defects.