Identification and tissue-specific expression of a NADH-dependent activity of dihydropyrimidine dehydrogenase in man.
Homogenates of human liver and human fibroblasts were able to convert thymine into dihydrothymine in the presence of NADH whereas almost no NADH-dependent activity could be detected in human lymphocytes. The different tissue distribution of the NADH-dependent activity suggests that different types of human dihydropyrimidine dehydrogenase exist. Both types of human liver dihydropyrimidine dehydrogenase showed a comparable affinity towards thymine, NADH and NADPH. Only a ten-fold lower Vmax value was observed for the NADH-dependent enzyme. During partial purification of the NADPH-dependent enzyme, on a 2', 5' - ADP Sepharose 4B column, the NADH-dependent activity was completely lost. Neither type of activity was retained on a 5' - AMP Sepharose 4B column.
Van Kuilenburg
A B
AB
University of Amsterdam, Division of Clinical Chemistry, The Netherlands.
Van Lenthe
H
H
Van Gennip
A H
AH
D002478:Cells, Cultured; D042943:Dihydrouracil Dehydrogenase (NADP); D005347:Fibroblasts / Q000201:enzymology; D006801:Humans; D007700:Kinetics; D008099:Liver / Q000166:cytology / Q000201:enzymology; D008214:Lymphocytes / Q000201:enzymology; D009243:NAD / Q000378:metabolism* / Q000494:pharmacology; D010088:Oxidoreductases / Q000378:metabolism*; D012680:Sensitivity and Specificity; D013936:Thymidine / Q000378:metabolism
D009243:NAD; D010088:Oxidoreductases; D042943:Dihydrouracil Dehydrogenase (NADP); D013936:Thymidine