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P6635 Sigma

Phosphorylase b from rabbit muscle

lyophilized powder, ≥20 units/mg protein

Synonym: α-Glucan Phosphorylase, 1,4-α-D-Glucan:orthophosphate α-D-glucosyltransferase, Glycogen Phosphorylase



Related Categories 2.4.x.x Glycosyltransferases, 2.x.x.x Transferases, Biochemicals and Reagents, Cell Biology, Enzyme Class Index,
Quality Level   PREMIUM
form   lyophilized powder
mol wt   mol wt 97,200 Da by calculation
purified by   2× crystallization
impurities   ~0.01 μmol/mg protein 5′-AMP (This low level will not interfere with phosphorylase and phosphorylase kinase assays.)
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


Frequently Asked Questions

Frequently Asked Questions are available for this Product.


10, 25, 100 mg in poly bottle

5 mg in glass bottle

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)


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.

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.

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.

Price and Availability

Safety & Documentation

Safety Information

NONH for all modes of transport
WGK Germany 
Protocols & Articles


Insulin Signaling and Energy Homeostasis

Glucose metabolism is regulated by the opposing actions of insulin and glucagon. Insulin is released from pancreatic ß cells in response to high blood glucose levels and regulates glucose metabolism ...
Linda Stephenson, Ph.D.
Biofiles v6 n4, 2011
Keywords: Apoptosis, Biological processes, Carboxylations, Catalog, Diabetes, Gene expression, Gluconeogenesis, Glycolysis, Hormones, Metabolism, Metabolites, Transcription, Transduction, Type

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Enzymes & Proteins

Application Index | Enzyme Index | Substrate Index | Inhibitor Index | Cofactor Index | Lectin Index
Keywords: Cell signaling, Diagnostic, Drug discovery, Molecular biology

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92210 Timestrip Plus 0 °C
06693 Timestrip Plus -20 °C

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