How does enzyme concentration affect the activity of an enzyme?
This effect is much like that of the concentration of substrate, and you might also guess from the section on rates of reactions that increasing concentration will tend to increase reaction rate. And again, there is an optimum value. It’s obviously not exactly the same this time, though. This time you’re looking at the enzyme molecules. Each one of them is turning the substrate into the product as quickly as it possible can, but it takes a certain amount of time for the substrate to slot into the active site, undergo the change that it needs to undergo, and then leave the active site. The next substrate molecule can’t come in until the first one has left, so there is a limit to how quickly the enzyme can do its stuff. If you increase the enzyme concentration, there are more enzyme molecules kicking about in a given volume – so there’s more enzyme molecules about to perform whatever task they have. More substrate molecules can be turned into the product – and this effect increases, the
