5-Bromouracil

• 5-bromo -1H- pyrimidine-2 ,4 -dione ( IUPAC)
• 5 -BU

Fixed

310 ° C ( decomposition)

In water: <1 g · l -1 ( 24 ° C)

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5 - bromouracil ( BrU 5 - or 5- BU) is a heterocyclic organic compound with a Pyrimidingrundgerüst and two keto groups at positions 2 and 4, and a bromine at position 5 there is a derivative of uracil nucleobase. It acts as an antimetabolite base analog, or it serves as a substitute for thymine in DNA, and can produce mutations in DNA in the same manner as 2 -aminopurine and 5- chlorouracil. It is mainly used as an experimental mutagen.

With deoxyribose it forms the nucleoside 5 - bromodeoxyuridine.

In DNA replication such base analogues are incorporated into the DNA. In this case, the thymine is replaced by the bromouracil, so that it now is the base pairing of adenine -5- bromouracil.

5 - bromouracil is tautomeric, so that different properties in terms of base pairing are present. The keto form (left) is complementary to adenine, and can therefore be incorporated into the DNA during replication. The enol form (right) is complementary to guanine. It occurs more frequently in comparison to thymine. This means that 5- bromouracil facing in the DNA either adenine or guanine. The forms change frequently, so that the base-pairing properties may change at any time.

From the A- T base pair of DNA is a G-C base pair after replication. If, after such a change of a replication of the DNA, it may be the result of a mutation. These changes may, after a number of replication cycles always repeat, depending on whether 5 - bromouracil is present in the DNA molecule in the keto or enol form: an A - T pair is a G- C pair or G -C A-T.