Kinetics of renaturation of denatured DNA. I. Spectrophotometric results

Abstract The kinetics of renaturation of heat‐ or formamide‐denatured DNA have been studied by following the change of optical density at a constant temperature. Solvents of different ionic strength and various DNA samples have been used. At the lower ionic strengths studied, the reaction follows second‐order kinetics, substantiating the hypothesis that strands of native DNA separate upon denaturation and recombine during renaturation. As the ionic strength is increased at a constant temperature, the reaction deviates from simple second‐order behavior. This appears to be the result of the inhibition to rewinding caused by short helical segments in the denatured DNA which are more stable at the higher ionic strenth.