| Modification Notes |
DNA topoisomerases are nuclear enzymes that regulate the topological structure of DNA in eukaryotic cells by transiently breaking and rejoining DNA strands. Due to their roles in DNA replication, recombination, and transcription, DNA topoisomerases have been identified as targets of numerous anticancer drugs. Mitochondrial Topo I (DNA topoisomerase I, mitochondrial) is a 601 amino acid protein that primarily acts to relieve DNA strain that may occur during duplication of mitochondrial DNA. Although it is expressed ubiquitously, it is logically present at highest levels in tissues that require dense concentrations of mitochondria (ie: heart, skeletal muscle, brain and fetal liver). As a a type IB topoisomerase, mitochondrial Topo I requires a divalent metal, either calcium or magnesium, as well as an alkaline pH for optimal activity. |