Now, within skeleton muscle cells, phosphorase exist in two interconvertible forms. We have phosphorase A and we have phosphorase B. Now, each one of these phosphoralase enzymes in turn exist in two different states. We have the T state, known as the ten state and we have the r state, also known as the relaxed state. Now, what's the difference between the T state and the r state? Well, in the T state, as a result of the confirmation of the dimer structure, these active sites of the enzyme are partially blocked.