the rapid uptake of 5-fu and extensive degradation of bases and nucleosides are probably responsible for the inability of uracil and uridine to reverse the growth inhibition caused by 5-fu in carrot cells while , as shown earlier , phaseolotoxin ( ( n-phosphosulfamyl ) ornithinylalanylhomoarginine ) , an inhibitor of the arginine biosynthetic enzyme , ornithine transcarbamylase was capable of reducing 5-fu toxicity .
C0041917
uracil
C0016360
fu