Glycogen phosphorylase is one of the phosphorylaseenzymes(EC2.4.1.1). It breaks up glycogeninto glucosesubunits. Glycogenis left with one less glucosemolecule, and the free glucosemolecule is in the form of glucose-1-phosphate. In order to be used for metabolism, it must be converted to glucose-6-phosphateby the enzyme phosphoglucomutase.

Glycogen phosphorylase can only act on linearchainsof glycogen(a 1-4 glycosidic linkage). Its work will immediately come to a halt four residues away from a 1-6 branch(which are exceedingly common in glycogen). In these situations, a debranching enzymeis necessary, which will straighten out the chain in that area. Additionally, an alpha 1-6 glucosidaseenzymeis required to break the remaining 1-6 residue that remains in the new linear chain. After all this is done, glycogen phosphorylase can continue.

An insulinstimulated enzyme known as phosphoprotein phosphatase(PP-1) inactivates glycogen phosphorylase to prevent glycogen break up.

GPBB - a sensitive marker for the AMI diagnosis within 4 hours after the onset of chest pain. It has also been shown that GPBB is increased in a considerable proportion of AMI patients within 2-3 hours from chest pain onset. GPBB is increased early in patients with unstable angina. GPBB can also be a sensitive marker for the detection of peri-operative myocardial ischaemia and infarction in patients undergoing coronary artery bypass grafting.

Glycogen Phosphorylase Human Recombinant produced in E.Coli is a single, non-glycosylated, polypeptide chain. The Human GPBB mature chain: 2 - 843 aa; that is a total of 842 aa having a molecular mass of 96695.96 Dalton. The theoretical pI is 6.40.

The GPBB is purified by proprietary chromatographic techniques.