Structural highlights
Function[PYGM_RABIT] Phosphorylase is an important allosteric enzyme in carbohydrate metabolism. Enzymes from different sources differ in their regulatory mechanisms and in their natural substrates. However, all known phosphorylases share catalytic and structural properties. Publication Abstract from PubMedC5-alkynyl and alkylfurano[2,3-d]pyrimidine glucopyranonucleosides have been synthesized and studied as inhibitors of glycogen phosphorylase b (GPb). Kinetic experiments have shown that most of these compounds were low micromolar inhibitors of the enzyme. The best inhibitor was 1-(beta-d-glucopyranosyl)-5-ethynyluracil (K(i)=4.7muM). Crystallographic analysis of these compounds in complex with GPb revealed that inhibitors with a long C5-alkynyl group exploited interactions with beta-pocket of the active site and induced significant conformational changes of the 280s loop compared to GPb in complex with compounds with a short C5-alkynyl group. The results highlight the importance in the length of the aliphatic groups used to enhance inhibitory potency for the exploitation of the hydrophobic beta-pocket. The best of the inhibitors had also a moderate effect on glycogenolysis in the cellular lever with an IC(50) value of 291.4muM. The binding of C5-alkynyl and alkylfurano[2,3-d]pyrimidine glucopyranonucleosides to glycogen phosphorylase b: Synthesis, biochemical and biological assessment.,Kantsadi AL, Manta S, Psarra AM, Dimopoulou A, Kiritsis C, Parmenopoulou V, Skamnaki VT, Zoumpoulakis P, Zographos SE, Leonidas DD, Komiotis D Eur J Med Chem. 2012 Jun 22. PMID:22770609[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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