P1 nuclease is a 36 kDa glycoprotein that cleaves its substrate at every position yielding nucleoside 5' monophosphates, and it does not recognize or act on double-stranded DNA [PMID: 9726413]. It is useful at removing single stranded strands hanging off the end of double stranded DNA and at completely cleaving melted DNA for simple DNA composition analysis. The enzyme is a phosphodiesterase cleaving the P-O3' bond with inversion of configuration at the phosphorus, but also acts as a phosphomonesterase removing 3'-terminal phosphate groups. It has no apparent specificity for bases.
Defined by 10 residues: TRP:A-1HIS:A-6ASP:A-45ARG:A-48HIS:A-60HIS:A-116ASP:A-120HIS:A-126HIS:A-149ASP:A-153