Now, because skeleton muscle cells and liver cells have slightly different functions in terms of what they actually do with the glucose, once they release the glucose from glycogen, they also regulate glycogen phosphorylase in slightly different ways. So in this lecture, I'd like to focus on how the skeleton muscle cells actually regulate glycogen phosphorylase. In the next lecture, we're going to focus on liver cells and discuss how they regulate glycogen breakdown via the regulation of glycogen phosphorase. Now, glycogen for sporlase is actually a dimer molecule. It consists of two polypeptide subunits and it is an allosteric enzyme. What that means is there exists certain types of molecules inside our cells that can actually either inhibit or activate activity of glycogen phosphorase.