Fluorouracil vs Uracil: what is the difference?

How they differ

Fluorouracil is uracil, one of the four building blocks of RNA, with a single fluorine atom where uracil has a hydrogen: C4H3FN2O2 at 130.1 against C4H4N2O2 at 112.1. Fluorine is close enough in size to hydrogen that cells take the fake building block up and process it like the real one. Once inside, it jams thymidylate synthase, the enzyme cells need to make DNA's thymine, and it is built into RNA in uracil's place, which stops fast-dividing cancer cells. Uracil is made by every living cell, while fluorouracil, known as 5-FU, was designed in 1957 as one of the first rationally planned cancer medicines.

Side by side

Common questions

What is the difference between Fluorouracil and Uracil?

Fluorouracil is uracil, one of the four building blocks of RNA, with a single fluorine atom where uracil has a hydrogen: C4H3FN2O2 at 130.1 against C4H4N2O2 at 112.1. Fluorine is close enough in size to hydrogen that cells take the fake building block up and process it like the real one. Once inside, it jams thymidylate synthase, the enzyme cells need to make DNA's thymine, and it is built into RNA in uracil's place, which stops fast-dividing cancer cells.

Is Fluorouracil bigger than Uracil?

Fluorouracil is the heavier molecule, 130.08 g/mol against 112.09 g/mol for Uracil. Fluorouracil is C4H3FN2O2 and Uracil is C4H4N2O2.