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P6635

Sigma-Aldrich

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

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About This Item

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

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

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General description

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.

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
  • 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

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. 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.

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)

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

Certificates of Analysis (COA)

Search for Certificates of Analysis (COA) by entering the products Lot/Batch Number. Lot and Batch Numbers can be found on a product’s label following the words ‘Lot’ or ‘Batch’.

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C Villar-Palasi et al.
Proceedings of the National Academy of Sciences of the United States of America, 67(1), 345-350 (1970-09-01)
Phosphorylase b kinase activity, as present in resting muscle in the non-activated form, appears to be ample to account for the fast appearance of phosphorylase a observed with muscle contraction. The kinase activity is repressed by free ATP and stimulated
Shanshan Qin et al.
Frontiers in plant science, 7, 1315-1315 (2016-09-16)
Two isoforms of starch phosphorylase (PHO; EC 2.4.1.1), plastidic PHO1 and cytosolic PHO2, have been found in all plants studied to date. Another starch phosphorylase-like gene, PHO3, which is an ortholog of Chlamydomonas PHOB, has been detected in some plant
The conversion of lobster muscle phosphorylase a to b and phosphorylase b to a.
R W COWGILL
The Journal of biological chemistry, 234, 3154-3157 (1959-12-01)
Y Kida et al.
The Journal of clinical investigation, 89(2), 610-617 (1992-02-01)
Insulin-stimulated glycogen synthase activity in human muscle is reduced in insulin-resistant subjects. Insulin regulation of human muscle glycogen synthase may require activation of a type-1 protein phosphatase (PP-1). We investigated the change of phosphorylase phosphatase and glycogen synthase activities in
Studies on the allosteric activation of glycogen phosphorylase b by Nucleotides. I. Activation of phosphorylase b by inosine monophosphate.
W J Black et al.
The Journal of biological chemistry, 243(22), 5892-5898 (1968-11-25)
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