Properties of DNA plus Dipropylsulfoxide or Dibutylsulfoxide plus Water Ternary Solutions

Aqueous solutions of DNA in the presence of dipropylsulfoxide (DPSO) and of dibutylsulfoxide (DBSO) have been studied using UV-vis spectroscopy and density measurements. It has been shown that significant thermal denaturation of DNA occurs when DPSO or DBSO are present. The results obtained were compared with those obtained previously with dimethylsulfoxide (DMSO) and diethylsulfoxide (DESO). It is suggested that the lowering of the transition enthalpy with increasing length of the carbon chain of the dialkylsulfoxides is due to significance contribution from hydrophobic interactions.