Comparison of the pyrimidine nucleoside phosphorylase activity in human tumors and normal tissues.
The novel fluoropyrimidine, 5'-deoxy-5-fluorouridine (5'-dFUDR) has strong tumor-inhibiting effect without severe cytotoxic effects on the normal cells. This pro-drug is metabolized by the enzyme pyrimidine nucleoside phosphorylase (PN'ase) to the active form 5-fluorouracil. Comparative determinations of pyrimidine nucleoside phosphorylase activity in tissue extracts revealed a significantly higher activity in the human gastrointestinal cancer tissues (6.84 +/- 0.70 nmol/mg protein) than in normal tissues from the same organ (2.37 +/- 0.21 nmol/min/mg protein).
Choong
Y S
YS
Department of Medicine, University of Auckland, School of Medicine, New Zealand.
Lee
S P
SP
Alley
P A
PA
D003110:Colonic Neoplasms / Q000201:enzymology*; D005467:Floxuridine / Q000378:metabolism; D005472:Fluorouracil / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D010430:Pentosyltransferases / Q000378:metabolism*; D011355:Prodrugs / Q000378:metabolism; D057845:Pyrimidine Phosphorylases; D013053:Spectrophotometry; D013274:Stomach Neoplasms / Q000201:enzymology*
D011355:Prodrugs; D005467:Floxuridine; D010430:Pentosyltransferases; D057845:Pyrimidine Phosphorylases; D005472:Fluorouracil; C025034:doxifluridine