Not available outside of the UK & Ireland.

Application

The enzyme from Sigma has been used in the calibration of Sepharose C1-6B columns while studying the molecular weight of methylamine dehydrogenase subunits. It has been used in ion mobility-mass spectrometry studies of phosphorylase B ions that have been generated with supercharging reagents, in charge-reducing buffer. It has also been used for the preparation of p³² labeled phosphorylase A using phosphorylase kinase and [³²P]ATP.

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.

Biochem/physiol Actions

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.

Packaging

5 mg in glass bottle

10, 25, 100 mg in poly bottle

Package size based on protein content.

Physical form

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

Unit Definition

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.)