Isolation of a Mitochondrial DNA Topoisomerase From Human Leukemia Cells

Biochem Biophys Res Commun. 1984 May 31;121(1):77-86. doi: 10.1016/0006-291x(84)90690-9.


Mitochondria from human acute lymphoblastic leukemia cells contain an ATP-independent DNA topoisomerase which can relax negative and positive supercoils. This enzyme has been purified 200-fold by carboxymethyl-cellulose or double stranded DNA-cellulose chromatography. In contrast to the molecular weights reported for mitochondrial topoisomerases in other systems, the native leukemia enzyme has a molecular weight of 132,000 daltons as determined by gel permeation chromatography in buffer containing 0.4 M KC1. It also exhibits a sedimentation coefficient of 7.1 S when centrifuged through a 10-30% glycerol gradient in this high salt buffer. The enzyme is presumably a type I topoisomerase analogous to those found in rat liver and Xenopus laevis mitochondria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatography / methods
  • DNA Topoisomerases, Type I / isolation & purification*
  • DNA, Mitochondrial / metabolism
  • DNA, Neoplasm / metabolism*
  • DNA, Superhelical / metabolism
  • Humans
  • Leukemia, Lymphoid / enzymology*
  • Mitochondria / enzymology*
  • Molecular Weight
  • Protein Denaturation


  • DNA, Mitochondrial
  • DNA, Neoplasm
  • DNA, Superhelical
  • DNA Topoisomerases, Type I