Activation of topoisomerase II during partial purification by heparin-Sepharose chromatography

Partial purification of topoisomerase II from small samples (10(7)-10(8) cells) of human leukaemic cells was achieved by isolation of cell nuclei, hyper-osmotic extraction of nuclear proteins, sorption of nuclear proteins by heparin-Sepharose and elution with potassium phosphate. Similar results were obtained by gradient and batchwise elution. The calatylic activity of topoisomerase increased ca. eightfold after removal of ca. 95% of the contaminating nuclear proteins. The conserved enzymatic activity after partial purification indicates that the enzyme was not damaged. The half-life of enzymatic activity is increased by the chromatographic procedure. Owing to its high yield and technical simplicity, this could be a candidate procedure for the study of topoisomerase II in patient-derived blood samples.