lwlkarel at lwlkarel at
Mon Dec 5 02:55:13 EST 1994

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

Kind regards,

Karel Wernars, the Netherlands
lwlkarel at

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