P6635

Phosphorylase b from rabbit muscle

lyophilized powder, ≥20 units/mg protein, 2× crystallization

• Synonym(s): α-Glucan Phosphorylase, 1,4-α-D-Glucan:orthophosphate α-D-glucosyltransferase, Glycogen Phosphorylase
• CAS Number: 9012-69-5
• Enzyme Commission number: 2.4.1.1 (BRENDA, IUBMB)
• EC Number: 232-737-0
• MDL number: MFCD00131905
• UNSPSC Code: 12352204
• NACRES: NA.77

Properties

• biological source: rabbit muscle
• Quality Level: 300
• form: lyophilized powder
• specific activity: ≥20 units/mg protein
• mol wt: 97,200 Da by calculation
• purified by: 2× crystallization
• storage condition: (Keep container tightly closed in a dry and well-ventilated place)
• technique(s): mass spectrometry (MS): suitable
• impurities: ~0.01 μmol/mg protein 5′-AMP (This low level will not interfere with phosphorylase and phosphorylase kinase assays.)
• UniProt accession no.: A0A5F9CLZ9; A0A5F9CRR0; A0A5F9D1C4; A0A5F9DLL9
• foreign activity: phosphoglucomutase ≤1.0%; phosphorylase a ≤10%; phosphorylase kinase ≤0.5%; phosphorylase phosphatase, debrancher enzyme, AMPase and ATPase ≤0.1%
• storage temp.: −20°C

Description

General description

Research area: Cell Signaling

Glycogen phosphorylase (PG), a specialized complex allosteric enzyme[1] has an evolutionarily conserved gene sequence.[2] GP contains a family of three isozymes such as muscle GP (mGP), liver GP (lGP), and brain GP (bGP) in humans.[1]

Application

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[3]
• in ion mobility-mass spectrometry studies of phosphorylase B ions that have been generated with supercharging reagents, in the charge-reducing buffer[4]
• for the preparation of p³² labeled phosphorylase A using phosphorylase kinase and [³²P]ATP[5]
• in phosphorylase phosphatase assay[6]
• in enzyme assay as a positive control to ensure the reaction system for the activity determination was adopted[7]

Biochem/physiol Actions

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[8]. Phosphorylase b is activated by inosine monophosphate[9]. 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.[2] 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.[10]

Packaging

Package size based on protein content.

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.)

Physical form

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

Safety Information

• Storage Class Code: 11 - Combustible Solids
• WGK: WGK 3
• Flash Point(F): Not applicable
• Flash Point(C): Not applicable
• Personal Protective Equipment: dust mask type N95 (US), Eyeshields, Gloves