And once we form phosphorase, this enzyme basically initiates step one of glycogen breakdown. Now, we also said that the enzyme that catalyzes this step is known as phosphorlase kinase. So ultimately what phosphorase kinase does is it takes sulfosphoryl groups from two ATP molecules and places them onto Seren residues found on phosphorase B and that creates phosphorase A. Now, the question that I'd like to address in this lecture is what exactly activates phosphoralase kinase? What exactly allows this molecule to carry out this process in the first place? So once again, phosphorase kinase is the enzyme that catalyzes the conversion of phosphorase B in the T state into phosphorlase A, which predominates in the R state.