Topoisomerase I

Topoisomerase I is a subfamily of topoisomerases that are involved in the topology of DNA, particularly during transcription and DNA replication. There are two main types of topoisomerase I: type IA and IB. Type IA can only relax negatively supercoiled DNA while type IB can introduce positive supercoils. Type IA enzymes can cleave a single strand of supercoiled DNA to form a 5'- phosphotyrosyl intermediate while IB enzymes form a 3'-phosphotyrosyl intermediate. Topoisomerase I enzymes can be used for relaxing positively and negatively supercoiled DNA in certain molecular biology experiments. Visit the supplier page for more enzyme information.