Phosphorylase b from rabbit muscle has been used as a molecular weight marker in 12% polyacrylamide gel for keratinase, and stress-70 protein.
Phosphorylase b is used to study the conversion mechanism of inactive phosphorylase b to active phosphorylase in muscle. Phosphorylase b is used to study which factors influence the conversion of phosphorylase b to phosphorylase a such as temperature, AMP, fluoride and detergents. It is used to study phosphorylase b deficiency mutations.
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.
Phosphorylase b is a non-active form and is present in resting muscle. Phosphorylase b kinase activity increases significantly when the Mg2+:ATP ratio exceeds 1. The breakdown of ATP during muscle contraction is thought to trigger in vivo conversion of phosphorylase b into a. Phosphorylase b is activated by inosine monophosphate.
