And this describes the fact that the second step takes place much slower than that initial step. And so this is a two step catalytic mechanism that basically generalizes what takes place inside climate trypsin. So the first step is the fast oscillation step in which the Acyl group is added onto the enzyme and then the amide is released. And it's the amide that is used to basically determine what the color change is. We use it to basically determine how much light is absorbed. And then in the second step, the second step is a much smaller step.