So the product of the concentration of the enzyme in the substrate divided by the complex concentration is equal to K minus one plus K two divided by K one. And instead of using these three rate constants, we basically set this ratio equal to a new ratio defined by uppercase K with the M subscript. And this is known as the Michaelis constant. And the Makalis constant is actually a very important constant, as we'll see in the next lecture. And the units of Michael's constant are concentration. So we'll talk much more about this in the next lecture and let's designate this as equation number four.