BIOL 2020 Study Guide - Final Guide: Glycogen Phosphorylase, Phosphorylase Kinase, Glycogen Synthase
Document Summary
Liver and skeletal , higher concentration in liver, but more in mass in skeletal. Regulatory enzyme in glycogen breakdown, by adding inorganic phosphates to make glucose-1-phosphate, advantageous because released sugar has a phosphate, can only remove glycosyl residues 4 away from branched point. 10 residues are branched, stops after releasing 6 glucose molecules. Transferase: shifts blck of 3 glu molec from one branch to another and alpha 1-6 glucosidase: releases branch (hydrolyzes) at 1-6 glycosidic bond. Takes glucose 1-phosphate and changes it to glucose 6-phosphate so it can enter metabolic stream, has phosphorylated serine residue in active site, intermediate is glucose 1,6-biphosphate. Regulated by allosteric enzymes(response to energy states) , reversible phosphorylation (response to hormones), A=phosphorylated and in r state, b=not phosphorylated and in t state (open active site) In muscles with high amp levels, atp, competes with amp , energy charge of the cell, g6p (feedback inhibition)
