Denaturation temperature

(of DNA), Tm; the temperature at which 50% of a given DNA species are double-stranded and 50% have denatured and are single-stranded

Description
The denaturation temperature, besides dependencies on salt and pH conditions of the environment, depends on the base composition (e.g. the percentage of G and C residues, the so-called GC content) and on the length of DNA molecules.

Practical application
In most cases in practice the denaturation temperature can be used to distinguish different DNA species from one another, in combination with dyes whose fluorescence depends on the presence of double-stranded DNA. At a steadily rising temperature and around the denaturation temperature of a predominant DNA species, that fluorescence will experience a quantifiable drop. The denaturation temperature of DNA species is of critical importance for all applications of the polymerase chain reaction (PCR). Syn melting temperature