We provide potential energy surfaces for the stretching of bonds within the active center of topoisomerase, taking into account increasing levels of complexity for the representation of the system as well as conformational effects. The reported data support the specificity that the composition of the molecules, their environment and the conformational effects of the system can bring to bond-breaking reactions. These findings further the idea that the environmental dependence can be used to selectively induce (or suppress) the breaking of a bond between two particular atoms depending on the surrounding groups. (C) 2014 Elsevier By. All rights reserved.