2′-terminator related pyrophosphorolysis activated polymerization

A method of removing a nucleotide from an oligonucleotide, the method comprising:

• incubating at least one target nucleic acid with:
• pyrophosphate;
• at least a first biocatalyst comprising a pyrophosphorolysis activity, and
• at least one oligonucleotide comprising a 2′-terminator nucleotide, which oligonucleotide is at least partially complementary to at least a first subsequence of the target nucleic acid,
• under conditions whereby the first biocatalyst removes at least the 2′-terminator nucleotide from the oligonucleotide to produce a removed 2′-terminator nucleotide and a shortened oligonucleotide, thereby removing the nucleotide from the oligonucleotide.