A PCR kit-of-parts is described. The kit-of-parts comprises a first oligonucleotide bound to a bead by a cleavable linker; a second oligonucleotide bound to a bead by a cleavable linker; and an enzyme bound to a bead by a cleavable linker; wherein the first and second oligonucleotide form an oligonucleotide pair complementary to a nucleic acid of interest and the enzyme is capable of extending nucleic acid strands; and each cleavable linker is independently selected from a photocleavable linker and a thermally cleavable linker. Also described is a method of performing PCR and a PCR system.