Biochemistry Deficiency of which of the following enzyme leads to toxicity of 5-fluorouracil? A Purine nucleoside phosphorylase B Dihydropyrimidine dehydrogenase C PRPP synthase D Adenosine deaminase 💡 Explanation Deficiency of which of the following enzyme leads to toxicity of 5-fluorouracil? ✓ Correct Answer: B. Dihydropyrimidine dehydrogenase