Well, it turns out that this is what we actually use to measure the catalytic efficiency of enzymes. So how enzymes or how efficient are enzymes in catalyzing a certain type of substrate? So let's remember what Kcat means and let's remember what Km means because if we remember what these two quantities mean individually, we can then basically decipher what the meaning is behind this ratio. So let's begin with Kcat. So Kcat, as we discussed in the previous lecture, is known as the turnover number. And Kcat basically describes how many of the substrate molecules are transformed into the product molecules per unit time, per single active site, per single enzyme.