[Spectrophotometric study of DNA complexes with dodecyltrimethylammonium bromide]

Multistep nature of complex formation of bromide dodecyltrimethylammonium (DTMA) with thymus DNA is shown by spectrophotometric method application in the range of 220-600 nm. While adsorbing DTMA DNA undergoes some structural changes. DTMA concentration raise from 0.4 to 0.8 mM per DNA provokes hydrophobic layer formation leading to following aggregation of the complexes. The analysis of light scattering in the range of 340-600 nm estimated the size of these aggregates. Assuming that these particles are spherical, their diameter appeared to be 95-110 nm.