The theory of the deoxyribonucleic acid - ribonucleic acid hybridization reaction.

A general equation is derived describing data of DNA-RNA hybridization in the presence of a competing self-annealing reaction of RNA. The well known double-reciprocal relation and the Scatchard equation are shown to be limiting cases of this general equation. Some new hybridization data at various temperatures are presented and analysed by using the new equation. The results can only be explained if we assume that the behavior of DNA towards single RNA molecules is the same as that towards the annealed form, (RNA12. The variation of the equilibrium constant of the hybridization reaction with temperature is small, indicating a small heat of reaction. The maximum amount of hybridized RNA at equilibrium appears to be independent of temperature.