So the concentration of this remains the same even though this concentration and this can actually change over time. And by making that steady state assumption, we were able to basically create the following Michael's constant. So Km, we said, was equal to K minus one plus K two divided by K one, where K minus one is simply the rate constant for this reaction, the dissociation of the enzyme substrate complex back into the enzyme and the substrate. So when the substrate essentially dissociates from the active site we produce back this enzyme and a substrate that K minus one. K one is basically the association, the formation of this enzyme substrate complex. And K two is the rate constant for this reaction, the dissociation of the enzyme substrate complex into the product molecule and that enzyme.