But the other three subunits basically have regulatory abilities. And as we'll discuss in just a moment, it's the beta subunits and the delta subunits which are ultimately responsible for fully activating the phosphorylase kinase. So during times of rapid and sudden strain use activity, we know that our body begins producing and releasing hormones into our bloodstream. And what these hormones ultimately do is they allow our body, they allow the cells of our body to actually activate these beta subunits and they activate the beta subunits by attaching phosphoryl groups. So when we release the hormones that ultimately basically these four beta subunits to form the following structure. Now, although this structure does contain partial activity, it is not yet fully functional.