But what it means to approach asymptotically is it never quite reaches it. So the red curve is never going to actually reach that VMAX quantity. Now that's problematic because we want to be able to calculate what v max actually is. And in fact, if we can't calculate what v max is, then we cannot calculate what the Km value is, the Macalus constant. So remember, the Mikalus constant basically describes the affinity of that substrate for the active side. And the Km value is the concentration of that substrate at which that enzyme operates at a velocity that is exactly half of that v max value.