5-bromouracil

Structural formula
General
Surname	5-bromouracil
other names	5-bromo-1 H -pyrimidine-2,4-dione ( IUPAC ); 5-BU;
Molecular formula	C 4 H 3 BrN 2 O 2
External identifiers / databases
EC number	200-084-0
ECHA InfoCard	100,000,077
PubChem	5802
Wikidata	Q238477
properties
Molar mass	190.98 g mol −1
Physical state	firmly
Melting point	310 ° C (decomposition)
solubility	in water: <1 g l −1 (24 ° C)
safety instructions
GHS labeling of hazardous substances Caution
H and P phrases	H: 302
	P: no P-phrases
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

5-Bromuracil ( 5-BrU or 5-BU ) is a heterocyclic organic compound with a pyrimidine backbone. It is a derivative of the nucleobase uracil with an additional bromine in position 5. It acts as an antimetabolite or base analog , it serves as a substitute for thymine in the DNA and may comprise DNA mutations in the same manner as 2-aminopurine and 5-chlorouracil produce . It is mainly used as an experimental mutagen .

With deoxyribose it forms the nucleoside 5-bromodeoxyuridine . With ribose it forms the nucleoside 5-bromouridine .

During DNA replication , these base analogs are incorporated into the DNA. In this case, the thymine is replaced by the bromuracil, so that the base pairing adenine – 5-bromuracil now occurs.

properties

5-bromouracil is tautomeric , so that there are different properties with regard to the base pairing. 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 compared to thymine. This means that 5-bromouracil is opposed to either adenine or guanine in the DNA. The shapes change more frequently, so the base pairing properties can change at any time.

After replication, the A – T base pair of the DNA becomes a G – C base pair. If the DNA replicates after such a change, a mutation can result. These changes can repeat themselves over and over again after a series of replication cycles, depending on whether 5-bromouracil is present in the DNA molecule in the keto or enol form: an A – T pair becomes a G – C pair or a G – C one AT. From 5-bromouracil, by mild hydrolysis 5-hydroxyuracil be generated.

Individual evidence

↑ ^a ^b Data sheet 5-bromouracil (PDF) from Merck , accessed on February 7, 2011.
↑ ^a ^b Data sheet 5-Bromouracil from Sigma-Aldrich , accessed on March 18, 2011 ( PDF ).

literature

Albert L. Lehninger : Biochemie , 2nd edition, Verlag Chemie, Weinheim 1983, ISBN 3-527-25688-1 , p. 720.
Lubert Stryer : Biochemie , 4th edition, Spectrum Akademischer Verlag, Heidelberg / Berlin / Oxford 1996, ISBN 3-86025-346-8 , pp. 850-851.

[Merck-1] Data sheet 5-bromouracil (PDF) from Merck , accessed on February 7, 2011.

[Sigma-2] Data sheet 5-Bromouracil from Sigma-Aldrich , accessed on March 18, 2011 ( PDF ).