Figure 2.

Metabolic overview illustrating the critical position of DPD in the metabolism of 5-FU as well as the natural pyrimidines uracil and thymine. More than 85% of administered 5-FU is catabolized via DPD. (Abbreviations: FUH2—dihydrofluorouracil; FUPA—fluoro-ureidopropionic acid; FBAL—Fluoro-beta- alanine; FUrd—Fluorouridine; FUMP -Fluoro- uridine monophosphate; FUDP—Fluorouridine diphosphate; FUTP—Fluoro uridine triphosphate; FUdR—Fluorodeoxyuridine; FdUMP—Fluorodeoxyuridine monophosphate; FdUDP—Fluorodeoxyuridine diphosphate; FdUTP—Fluorodeoxyuridine triphosphate; BVU—bromovinyl uracil).