Description_x000D_ General description_x000D_ Phosphorylase b is a dimer, usually exists in inactive form in the skeletal muscles. Equilibrium exists between an active relaxed (R) state and a less active tense (T). Phosphorylase b favors the T state. The enzyme possesses three domains, the N-terminal domain, glycogen-binding domain and the C-terminal domain._x000D_ Application_x000D_ Phosphorylase b from rabbit muscle has been used as a molecular weight marker in 12% polyacrylamide gel for keratinase, and stress-70 protein._x000D_ Phosphorylase b from rabbit muscle is to be used as a marker in SDS-PAGE. Phosphorylase b is used during chemical cross-linking studies as a SDS-PAGE molecular weight standard.