In fact, it's so common that nearly 30% of all the proteins and this includes enzymes in eukaryotic cells are actually phosphorylated. Now why is this method so common? Well as it turns out phosphorylation is a very effective, very efficient and a very convenient process and we'll see why that is. So in just a moment. First let's actually discuss the family of enzymes that are responsible for catalyzing controlling the rate of this phosphorylation process. So basically, just like any biological process that takes place inside our body is controlled by enzymes, this process of phosphorylation is also regulated by enzymes.