Figure 8.
Effects of DTT on EGCG activity toward topoisomerase II after DNA cleavage complexes are established. Data for human topoisomerase IIα (hTIIα; left panel) and topoisomerase IIβ (hTIIβ; right panel) are shown. Following DNA cleavage enhancement in the presence of 500 μM EGCG, topoisomerase II-DNA cleavage complexes were further incubated without DTT (−DTT; closed bars) or with 500 μM DTT (+DTT; open bars). Control reactions contained DNA and enzyme in the absence of compounds (hTIIα or hTIIβ), or cleavage complexes established in the presence of 25 μM 1,4-benzoquinone (BQ), 50 μM genistein (Gen), or 50 μM etoposide (Etop). Error bars represent standard deviations for three independent experiments.