title: Kinetics studies on the inhibition mechanism of pancreatic α-amylase by glycoconjugated 1H-1,2,3-triazoles: a new class of inhibitors with hypoglycemiant activity.
abstract: Glycoconjugated 1H-1,2,3-triazoles (GCTs) comprise a new class of glycosidase inhibitors that are under investigation as promising therapeutic agents for a variety of diseases, including type 2 diabetes mellitus. However, few kinetics studies have been performed to clarify the mode of inhibition of GCTs with their target glycosidases. Our group has previously shown that some methyl-β-D-ribofuranosyl-1H-1,2,3-triazoles that inhibit baker's yeast maltase were also able to reduce post-prandial glucose levels in normal rats. We hypothesized that this hypoglycemiant activity was attributable to inhibition of mammalian α-glucosidases involved in sugar metabolism, such as pancreatic α-amylase. Hence, the aim of this work was to test a series of 26 GCTs on porcine pancreatic α-amylase (PPA) and to characterize their inhibition mechanisms. Six GCTs, all ribofuranosyl-derived GCTs, significantly inhibited PPA, with IC(50)  values in the middle to high micromolar range. Our results also demonstrated that ribofuranosyl-derived GCTs are reversible, noncompetitive inhibitors when using 2-chloro-4-nitrophenyl-α-D-maltotrioside as a substrate. E/ES affinity ratios (α) ranged from 0.3 to 1.1, with the majority of ribofuranosyl-derived GCTs preferentially forming stable ternary ESI complexes. Competition assays with acarbose showed that ribofuranosyl-derived GCTs bind to PPA in a mutually exclusive fashion. The data presented here show that pancreatic α-amylase is one of the possible molecular targets in the pharmacological activity of ribofuranosyl-derived GCTs. Our results also provide important mechanistic insight that can be of major help to develop this new class of synthetic small molecules into more potent compounds with anti-diabetic activity through rational drug design.
authors: Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Bioquímica de Proteínas e Peptídeos, 21040-360, Brazil.
authors: Mario Roberto
authors: MR
authors: Senger
authors: Lucas da Costa Andrade
authors: Lda C
authors: Gomes
authors: Sabrina Baptista
authors: SB
authors: Ferreira
authors: Carlos Roland
authors: CR
authors: Kaiser
authors: Vitor Francisco
authors: VF
authors: Ferreira
authors: Floriano Paes
authors: FP
authors: Silva
mesh_terms: D000818:Animals; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000145:classification / Q000494:pharmacology*; D007004:Hypoglycemic Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D007700:Kinetics; D008958:Models, Molecular; D015394:Molecular Structure; D055292:Pancreatic alpha-Amylases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013329:Structure-Activity Relationship; D013552:Swine; D014230:Triazoles / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D004791:Enzyme Inhibitors; D007004:Hypoglycemic Agents; D014230:Triazoles; D055292:Pancreatic alpha-Amylases