Phosphorylase b from rabbit muscle

Research area: Cell Signaling

Glycogen phosphorylase (PG), a specialized complex allosteric enzyme has an evolutionarily conserved gene sequence. GP contains a family of three isozymes such as muscle GP (mGP), liver GP (lGP), and brain GP (bGP) in humans.

Phosphorylase b from rabbit muscle has been used:

• in the calibration of Sepharose C1-6B columns while studying the molecular weight of methylamine dehydrogenase subunits
• in ion mobility-mass spectrometry studies of phosphorylase B ions that have been generated with supercharging reagents, in the charge-reducing buffer
• for the preparation of p³² labeled phosphorylase A using phosphorylase kinase and [³²P]ATP
• in phosphorylase phosphatase assay
• in enzyme assay as a positive control to ensure the reaction system for the activity determination was adopted

Phosphorylase b is a non-active form and is present in resting muscles. 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. Glycogen phosphorylase (PG) enzyme plays a vital role in the first step of glycogenolysis. In the initial stage of glycogenolysis, glycogen phosphorylase(GP) breaks α-1,4- -glycosidic bonds, releasing the glucose-1-phosphate (G1P)molecule. When incubated with the proper concentrations of glucose-1-phosphate without the addition of primer, rabbit muscle phosphorylase B was found to be capable of forming protein-bound alpha-1,4 glucosyl chains.

Package size based on protein content.

Lyophilized powder containing lactose, 5′-AMP, and Mg(OAc)₂ (10 μmole per 100 mg protein)

One unit will form 1.0 μmole of α-D-glucose 1-phosphate from glycogen and orthophosphate in the presence of 5′-AMP, per min at pH 6.8 at 30 °C measured in a system containing phosphoglucomutase, NADP, and glucose 6-phosphate dehydrogenase. (One μmolar unit is equivalent to approx. 45 Cori units.)