Maximun UV absorbance for DNA - (Nov/17/2006 )

Hi all,

the maximin absorbance of DNA is at 260nm? or below 200nm? I found that many DNA spectra show that the absorbance of DNA at 200nm or below has a higher molar absoptivity than at 260nm. For example, this one here http://faculty.evansville.edu/be6/b4454/DNAspectrum.gif

This spectrum is taken online(may not be very reliable), but i found the same type of spectra in a few other websites. So, why many poeple say the max absorbance for DNA is at 260nm???

Thanks a lots!!

hi
the max absorbance of DNA is not at 260 nm but it's the more specific one. By taking at 230 for ex, you have phenols and salts that interfers with it. At 260, the relative absobance of other components is negligible in a pure preparation.