Purification and properties of DNA topoisomerase I from broccoli

Plant Mol Biol. 1992 Mar;18(5):865-71. doi: 10.1007/BF00019201.


We have purified a topoisomerase activity from broccoli (Brassica oleracea var. italica) to near homogeneity. The enzyme is an 80 kDa monomer as judged by gel filtration chromatography and SDS gel electrophoresis, though it may represent a proteolytic fragment of a larger protein. The enzyme is capable of removing both negative and positive supercoils in steps of one, does not absolutely require Mg2+, is only very weakly stimulated by NaCl, is inhibited by camptothecin, and cross-reacts with an antibody directed against human DNA topoisomerase I. These properties identify the enzyme as a eukaryotic type I topoisomerase.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Blotting, Western
  • Brassica / enzymology*
  • Camptothecin / pharmacology
  • Chromatography, Gel
  • DNA Topoisomerases, Type I / isolation & purification*
  • DNA Topoisomerases, Type I / metabolism
  • DNA, Superhelical / metabolism
  • Magnesium / metabolism
  • Plant Proteins / isolation & purification*
  • Plant Proteins / metabolism
  • Sodium Chloride / metabolism


  • DNA, Superhelical
  • Plant Proteins
  • Sodium Chloride
  • DNA Topoisomerases, Type I
  • Magnesium
  • Camptothecin