Bac Thieu ID: 0070573 Spring 2011 region and hold successions of Glycogen Phosphorylase Glycogen phosphorylase belongs to a super family glycosyltransferease. It function is hold fast a glucose from animal amylum at the 1-4 alpha glycosidic stick to which is the first and rate curb pace in degradation of animal starch (?-1,4-glucoside)n + Pi (? - 1,4-glucoside)n-1 + ?-glucose-1-P. It is a homodimer and individually subunit consists of about 850 residues with a put for animal starch storage, an industrious locate and two allosteric land sites. The active site of animal starch phosphorylase is buried robust inside the protein and provides a hydrophobic environs for degradation of glycogen. This environment prevents water from degradation of glycogen into glucose and glycogen slight ace monomer. The main product of glycogen degradation is glucose-1-phosphate. some(prenominal) glycogen and glucose-1-phophate products argon both in the ? reachs, a carbocation middling is necessary differently a Sn2 type of phospholysed would sort the ? glucose-1-phosphate. At the active site, the aldehyde of adermin phosphate (PLP) coenzyme forms a Schiff foot with Lys681 (the ground tackle sequence used is human colored form glycogen phosphorylase UniProt ID P06737).
The 5-phosphate root of PLP batch give a proton to an phosphate (HPO4-2) and at the very(prenominal) time the orthophosphate then can donate its other proton the type O of the divergence glycogen. Once protonated, the leaving glycogen breaks away and establish behind a carbocation glucose and a PLP indentured orthophosphate anion. The orthophosphate anion now is able to protonated the PLP and at the same time form an ? bond with the carbocation glucose and the product ?-glucose-1-phosphate is produced (Michelle.) (picture from first appearance to Structure, Function and Informatics - C. Tsai Wiley, 2007) To held the orthophosphate and the phosphate of PLP in enamour orientation, three hydrogen bonds is create amid Lys569, the peptide bond between Gly136 and Gly135,...If you indispensableness to get a full essay, order it on our website: Ordercustompaper.com
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