ethidiumbromide

[lwlkarel at rivm.nl]

bb1rofra at lucano (Antonio Rodriguez Franco) wrote:

>>I assume ethidium bromide increases the density of DNA. Is that is true,
>>does anybody know what the density of DNA should be in the presence and in 
>>the absence of EtBr ?.

EtBr is an compound that intercalates between the strands of dsDNA, thereby
decreasing the density of the DNA. The amount of EtBr that binds to a DNA
molecule depends on its structure. A covalently closed circular (ccc) plasmid
can absorb less than the open circular or linear form. Purification of plasmid
DNA by CsCl/EtBr buoyant density gradient centrifugation is based on this
priciple.

Kind regards,

Karel Wernars, the Netherlands
lwlkarel at rivm.nl