At that point, our reaction, our enzyme activity, has reached a maximum rate and this is known as the maximum velocity or VMAX. And the enzyme at this point is said to be saturated. And by increasing the concentration of substrate at this point we are basically not affecting the rate of our activity of the enzyme because all those active sites of all the enzymes are actually filled up or occupied. Now, let's take a look at the following diagram briefly. So our y axis is the velocity, which is basically another way of saying the rate or activity of that enzyme. Now the x axis represents the concentration of substrate.