Skip to main content
. Author manuscript; available in PMC: 2014 Apr 15.
Published in final edited form as: Chem Res Toxicol. 2013 Apr 4;26(4):622–628. doi: 10.1021/tx4000667

Figure 3.

Figure 3

GCG-induced DNA cleavage is mediated by topoisomerase II. Data for human topoisomerase IIα (hTIIα; left) and IIβ(hTIIβ; right) are shown. DNA cleavage control reactions were carried out in the absence of catechin (hTIIα or hTIIβ) or in the presence of 200 μM GCG but in the absence of enzyme (GCG). All other reactions contained topoisomerase II and 200 μM GCG. DNA cleavage reactions were terminated by the addition of SDS (SDS). To determine whether cleaved DNA was protein-linked, proteinase K treatment was omitted (-ProK). The reversibility of DNA cleavage was examined by adding EDTA prior to SDS (EDTA). The level of DNA cleavage in the absence of GCG was set to 1 and all other reactions were expressed relative to that value. Error bars represent standard deviations for three independent experiments.