Low temperature cycled PCR protocol for Klenow fragment of DNA polymerase I in the presence of proline

A method for performing cycled PCR at low temperatures, using the thermolabile Klenow fragment of DNA polymerase I, is reported. Application of proline as a buffer additive in the range of 3.0-5.5 M remarkably increases the thermal stability of the polymerase and decreases the denaturation temperature of DNAtemplate. This method might be applicable to a broad spectrum of thermolabile DNA polymerases in cycled PCR and other methods of DNA amplification.