Which of the following antiumor agents works by impairing de novo purine synthesis?: (A) Acyloguanosine, (B) 5-Fluorouracil, (C) Methotrexate (antifolate), (D) Allopurinol
Answer is C. Ans. is 'c' i.e., Methotrexate (antifolate) o Methotrexate and permetrexed are dihydrofolate reductase (DHF Rase) inhibitors. o These drug also inhibit thymidylate synthase and de novo purine synthesis, which contribute to methotrexate toxicity.