[The rate factor in DNA sedimentation studies]

Zimm theory was used to study the effect of the rate of centrifugation on the coefficient and the profile of sedimentation of a polydispersed single-stranded DNA. There was a good agreement between the calculated and experimental DNA sedimentograms in alkaline lysates of irradiated rat bone marrow cells. This approach permited to take the rate factor into consideration on the basis of the parameters necessary for the work of the rotor and the gradient. Simple formulae were obtained connecting the molecular mass of DNA with the rate and the time necessary for its centrifugation. Possible consequences of not taking the rate factor into account in centrifuging the polymer DNA molecules are discussed.