Figure 5.
GCG is a covalent topoisomerase II poison. Time courses for DNA cleavage mediated by human topoisomerase IIα (hTIIα; left) and IIβ(hTIIβ; right) are shown. Reactions were carried out in the absence (closed circles) or presence (open circles) of 500 μM DTT. DNA cleavage values were quantified relative to reactions carried out in the absence of GCG for 6 min. Error bars represent the standard deviations for three independent experiments.