So at the zero point at time zero we basically take our mixture of that special substrate and we mix it in with our enzyme and now our reaction begins and notice what kind of curve we actually produce. So we see that initially we have a very steep slope, a very large slope and then the slope begins to level off and so here the rate of the reaction is low but here the rate of the reaction is very fast. Now, what exactly does that tell us about the reaction mechanism of Chimetrypsin? Well, what it tells us is we have this initial fast birth stage and that describes the first step of the reaction. And the first step of reaction, the actual binding of the substrate onto that catalytic seren of the active side is a very quick step. But as soon as that step takes place, we have a second step.