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 PubMedWe present a study on the binding of gallic acid and its dimer ellagic acid to glycogen phosphorylase (GP). Ellagic acid is a potent inhibitor with Kis of 13.4 and 7.5muM, in contrast to gallic acid which displays Kis of 1.7 and 3.9mM for GPb and GPa, respectively. Both compounds are competitive inhibitors with respect to the substrate, glucose-1-phoshate, and non-competitive to the allosteric activator, AMP. However, only ellagic acid functions with glucose in a strongly synergistic mode. The crystal structures of the GPb-gallic acid and GPb-ellagic acid complexes were determined at high resolution, revealing that both ligands bind to the inhibitor binding site of the enzyme and highlight the structural basis for the significant difference in their inhibitory potency. Natural flavonoids as antidiabetic agents. The binding of gallic and ellagic acids to glycogen phosphorylase b.,Kyriakis E, Stravodimos GA, Kantsadi AL, Chatzileontiadou DS, Skamnaki VT, Leonidas DD FEBS Lett. 2015 May 14. pii: S0014-5793(15)00389-0. doi:, 10.1016/j.febslet.2015.05.013. PMID:25980608[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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