Abstract
If a branched multistep editing mechanism is implemented by an enzyme with a single site for the specific substrates, there is no reason to believe that the number of testing steps is fixed and cannot be controlled by some external factors. The paper considers the mechanisms of single- or multistep editing done in response to various factors, particularly to the value of displacement from the reaction equilibrium. To avoid a complicated analysis of a fully specified case, which would be likely to obscure the general significant features, the operating modes of those mechanisms are estimated using the method of minimizing associated information gains. It turns out that sufficiently far from equilibrium the variable mechanisms can essentially operate just as well as the fixed multistep mechanisms.