title: Ranitidine induces inhibition and structural changes in sucrase.
abstract: Ranitidine is an antagonist of histamine-2 (H(2)) receptor. It is employed to treat peptic ulcer and other conditions in which gastric acidity must be reduced. Sucrase is a hydrolytic enzyme that catalyzes the breakdown of sucrose to its monomer content. A liquid of yeast sucrase was developed for treatment of congenital sucrase-isomaltase deficiency (CSID) in human. In this study, the effect of ranitidine on yeast sucrase activity was investigated. Our results showed that ranitidine binds to sucrase and inhibits the enzyme in a noncompetitive manner. The K(i) and IC(50) values were measured to be about 2.3 and 2.2 mM, respectively. Fluorescence measurement showed conformational changes after binding of ranitidine to the enzyme. The fluorescence spectra showed that ranitidine could bind to both free enzyme and enzyme-substrate complex, which was accompanied with reduction of emission intensity and red shift production.
authors.affiliation: Bioresearch Laboratory, Faculty of Biological Sciences, Shahid Beheshti University, GC Tehran, Iran. d_mtehrani@sbu.ac.ir
authors.forename: Dariush
authors.initials: D
authors.lastname: Minai-Tehrani
authors.forename: Mina
authors.initials: M
authors.lastname: Ghaffari
authors.forename: Zahra
authors.initials: Z
authors.lastname: Sobhani-Damavandifar
authors.forename: Saeed
authors.initials: S
authors.lastname: Minoui
authors.forename: Sana
authors.initials: S
authors.lastname: Alavi
authors.forename: Rahele
authors.initials: R
authors.lastname: Osmani
authors.forename: Shiva
authors.initials: S
authors.lastname: Ahmadi
mesh_terms: D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D011487:Protein Conformation / Q000187:drug effects; D011899:Ranitidine / Q000737:chemistry / Q000494:pharmacology*; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D013329:Structure-Activity Relationship; D013393:Sucrase / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D011899:Ranitidine; D013393:Sucrase