Abstract: The invention relates to a composition comprising a first modified thermostable enzyme exhibiting 3?exonuclease activity but essentially no DNA polymerase activity and a second modified thermostable enzyme exhibiting DNA polymerase activity, whereas the fidelity of an amplification process is enhanced by the use of the composition in an amplification process in comparison to the use of the single second enzyme in an amplification process and, whereas said first and said second modified thermostable enzyme is reversibly modified by an inhibiting agent which results in essentially complete inactivation of enzyme activity, wherein incubation of said first and said second modified thermostable enzyme in an aqueous buffer at alkaline pH at a temperature less than 25° C. for 20 minutes results in no significant increase in the activity of said first and said second modified thermostable enzyme, wherein incubation at a temperature greater than 50° C.

Abstract: A purified thermostable enzyme is derived from the thermophilic archaebacterium Archaeoglobus fulgidus. The enzyme can be native or recombinant, is stable under PCR conditions and exhibits double strand specific exonuclease activity. It is a 3?–5? exonuclease and cleaves to produce 5?-mononucleotides. Thermostable exonucleases are useful in many recombinant DNA techniques, in combination with a thermostable DNA polymerase like Tag especially for nucleic acid amplification by the polymerase chain reaction (PCR).

Abstract: A purified thermostable enzyme is derived form the thermophilic archaebacterium Archaeoglobus fulgidus. The enzyme can be native or recombinant, is stable under PCR conditions and exhibits double strand specific exonuclease activity. It is a 3?-5? exonuclease and cleaves to produce 5?-mononucleotides. Thermostable exonucleases are useful in many recombinant DNA techniques, in combination with a thermostable DNA polymerase like Taq especially for nucleic acid amplification by the polymerase chain reaction (PCR).

Abstract: The invention relates to a composition comprising a first modified thermostable enzyme exhibiting 3′exonuclease activity but essentially no DNA polymerase activity and a second modified thermostable enzyme exhibiting DNA polymerase activity, whereas the fidelity of an amplification process is enhanced by the use of the composition in an amplification process in comparison to the use of the single second enzyme in an amplification process and, whereas said first and said second modified thermostable enzyme is reversibly modified by an inhibiting agent which results in essentially complete inactivation of enzyme activity, wherein incubation of said first and said second modified thermostable enzyme in an aqueous buffer at alkaline pH at a temperature less than 25° C. for 20 minutes results in no significant increase in the activity of said first and said second modified thermostable enzyme, wherein incubation at a temperature greater than 50° C.