So basically, on the reactant side, we have the enzyme by itself, we have the substrate by itself, and then a reaction takes place that has a raid constant of K one. And this reaction basically is the reaction in which the substrate actually goes on and binds onto the active side of that enzyme to form the intermediate molecule, the enzyme substrate complex. Now, once we form the enzyme substrate complex, one of two things can take place. Either that substrate can actually dissociate from the active side before it is actually transformed into that product, and this reaction simply means we dissociate the complex back into the enzyme and the substrate. And the rate constant for this backward reaction is given by K minus one. But the other thing that can take place, and this is ultimately what we want to study in this lecture, is this reaction here.