Türkeş C.Söyüt H.Beydemir S.20.04.20192019-04-2020.04.20192019-04-2020141734-1140https://dx.doi.org/10.1016/j.pharep.2013.08.007https://hdl.handle.net/20.500.12403/800Background: In this study, we investigated the in vitro effects of calcium channel blockers (nifedipine, nitrendipine, isradipine, and amlodipine besylate) on the activity of paraoxonase-1 (PON1). Methods: PON1 was purified from human serum using simple chromatographic methods, including DEAE-Sephadex anion-exchange and Sephadex G-200 gel filtration chromatography. Results: The calcium channel blockers decreased the in vitro PON1 activity. The inhibition mechanism of amlodipine besylate was noncompetitive, whereas nifedipine, nitrendipine, and isradipine were competitive inhibitors. Conclusions: Our results showed that calcium channel blockers exhibit inhibitory effects on PON1 at low concentrations. The IC50 values for nifedipine, nitrendipine, isradipine, and amlodipine besylate were determined to be 0.121 mM, 0.130 mM, 0.255 mM, and 0.304 mM, respectively, and the Ki constants were calculated to be 0.222 ± 0.049 mM, 0.151 ± 0.067 mM, 0.286 ± 0.137 mM, and 0.321 ± 0.002 mM, respectively. © 2014 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.eninfo:eu-repo/semantics/closedAccessAmlodipine besylateIsradipineNifedipineNitrendipineParaoxonaseamlodipine besylateammonium sulfatearyldialkylphosphatase 1calcium channel blocking agentisradipinenifedipinenitrendipineamlodipinearyldialkylphosphatasecalcium channel blocking agentisradipinenifedipinePON1 protein, humananion exchange chromatographyarticlecompetitive inhibitioncontrolled studydrug bindingdrug effectdrug structureenzyme activityenzyme inhibitionfractionationgel filtration chromatographyhumanin vitro studyoxidative stressantagonists and inhibitorsdrug effectsmetabolismoxidative stressAmlodipineAryldialkylphosphataseCalcium Channel BlockersHumansIsradipineNifedipineNitrendipineOxidative StressAmlodipine besylateIsradipineNifedipineNitrendipineParaoxonaseamlodipine besylateammonium sulfatearyldialkylphosphatase 1calcium channel blocking agentisradipinenifedipinenitrendipineamlodipinearyldialkylphosphatasecalcium channel blocking agentisradipinenifedipinePON1 protein, humananion exchange chromatographyarticlecompetitive inhibitioncontrolled studydrug bindingdrug effectdrug structureenzyme activityenzyme inhibitionfractionationgel filtration chromatographyhumanin vitro studyoxidative stressantagonists and inhibitorsdrug effectsmetabolismoxidative stressAmlodipineAryldialkylphosphataseCalcium Channel BlockersHumansIsradipineNifedipineNitrendipineOxidative StressArticle661748010.1016/j.pharep.2013.08.007249053102-s2.0-84899623380N/AWOS:000334132900012Q3