Klentaq1 is named after Klenow fragment, and it is a similar N-terminal deletion (removing the 5"-[flap]exonuclease of Taq DNA polymerase). PCR tests show that Klentaq1 has improved fidelity (about 25%) and thermostability (about 2 degrees) relative to wild-type Taq, and it gives higher yields of amplicon. We speculate that the higher yields arise because at the end stages of a PCR reaction, the 5"-exonuclease can begin to attack the PCR product, but we are open to another opinion. Klentaq1 was used in the original formula for discovery of Long and Accurate PCR (Barnes, 1994; US patent 5,436,149). Klentaq1 also has inhibition resistance properties, tolerating up to 10% whole blood in a PCR reaction.

Since Klentaq1 lacks the 5 prime exonuclease activity, it is not suitable for TaqMan assays.