Study on the DNA behavior in surfactant solutions show that various surfactants could greatly affect the DNA conformations in solutions in the sequence of cationic surfactant (e. g. cetyltrimethylammonium bromide, CTMAB)>anionic surfactants (e. g. sodium dodecyl sulfate, SDS)> neutral surfactants (e. g. Triton X-100). CTMAB interacts with DNA by Coulombic forces and hydrophobicity. The interaction between anionic surfactants and DNA is relatively weak, while the effect of Triton X-100 on DNA is similar to that of solvent, which means that both of them affect DNA conformations by polarity and dielectric constant. The results indicate that Coulombic forces and hydrophobicity play an important role in the interaction between DNA and surfactant molecules.

Key words: DEOXYRIBONUCLEIC ACID, CONFORMATION, CALF, THYMUS GLAND, SURFACTANTS, ETHIDIUM BROMIDE, FLUOROSPECTROPHOTOMETRY, NSFC