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.
Glycogen phosphorylase is one of the phosphorylaseenzymes(EC22.214.171.124). 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.