Spliced protein is a DNA polymerase used in PCR reactions. PI-TfuI recognizes and cleaves a minimal sequence of 16 base pairs (bp, 5'-TTTTAGGTCGCTATAT-3') cutting after T-8 in supercoiled DNA with either Mn(2+) or Mg(2+) as cofactor. Yields 5'-phosphate and 3'-OH ends. It only cleaves linear DNA with Mn(2+) and requires a 19-bp minimal recognition sequence. PI-TfuII is a highly active homing endonuclease using Mg(2+) as cofactor. Its minimal recognition and cleavage site is 21 bp (5'-ACGCGGATACAGACGGCTTTT-3') cutting after -7 on both linear or circular DNA substrates. Yields 5'-phosphate and 3'-OH ends. Its endonuclease activity is strongly inhibited by the 3' digestion product, which remains bound to the enzyme after the cleavage reaction. a 2'-deoxyribonucleoside 5'-triphosphate + DNA(n) = diphosphate + DNA(n+1) For PI-TfuII intein endonuclease. For PI-TfuI intein endonuclease. Optimum temperature is 70 degrees Celsius. This protein undergoes a protein self splicing that involves a post-translational excision of the two intervening regions (inteins) followed by peptide ligation. Belongs to the DNA polymerase type-B family.