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. 2003 Jan-Feb;9(1-2):26–36.

Figure 1.

Figure 1

Inhibition of catalytic activity of L. donovani DNA topoisomerases I and II by DHBA. A: Structure of DHBA. B: Simultaneous addition of topoisomerase I, DHBA, and DNA. Lane 1, supercoiled pGEM4Z DNA; lane 2, DNA with 2 units of purified L. donovani topoisomerase I and 4% DMSO; lanes 3 to 7, inhibition of catalytic activity with increasing concentration of DHBA. SM, supercoiled monomer; NM/RM nicked or relaxed monomer. C: Simultaneous addition of topoisomerase I, camptothecin, and DNA. Lanes 1 and 2, supercoiled pGEM4Z DNA; lanes 3 to 7, inhibition of catalytic activity with increasing concentration of camptothecin. D: Inhibition of catalytic activity of L. donovani DNA topoisomerase II by DHBA and etoposide. Lane 1, control kDNA; lane 2, kDNA with 2 units of purified L. donovani topoisomerase II; lanes 3 to 5, simultaneous addition of topoisomerase II, kDNA, and increasing concentration of etoposide; lanes 6 to 10, same as lanes 3 to 5 but with increasing concentration of DHBA. E: Effect of dihydrolupeol on catalytic activity of L. donovani DNA topoisomerase I. Lane 1, supercoiled pGEM4Z DNA; lane 2, DNA with 2 units of topoisomerase I; lanes 3 to 5, simultaneous addition of DNA, enzyme, and increasing concentrations of dihydrolupeol. F: Effect of dihydrolupeol on catalytic activity of L. donovani DNA topoisomerase II. Lane 1, kDNA; lane 2, kDNA with 2 units of topoisomerase II; lanes 3 to 5, simultaneous addition of DNA, enzyme, and increasing concentrations of dihydrolupeol.