QSAR方法TEST软件用户指南

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1、User’sGuideforT.E.S.T.(version4.1)(ToxicityEstimationSoftwareTool)AProgramtoEstimateToxicityfromMolecularStructure©2012U.S.EnvironmentalProtectionAgencyTableofContentsPage1.INTRODUCTION32.THEORY73.EXPERIMENTALDATASETS214.VALIDATIONRESULTS295.USINGTHESOFTWARE506.REFERENCES6521.INTRODUCTION

2、QuantitativeStructureActivityRelationships(QSARs)aremathematicalmodelsthatareusedtopredictmeasuresoftoxicityfromphysicalcharacteristicsofthestructureofchemicals(knownasmoleculardescriptors).Acutetoxicities(suchastheconcentrationwhichcauseshalfoffishtodie)areoneexampleoftoxicitymeasureswhi

3、chmaybepredictedfromQSARs.SimpleQSARmodelscalculatethetoxicityofchemicalsusingasimplelinearfunctionofmoleculardescriptors:Toxicityaxbxc12wherex1andx2aretheindependentdescriptorvariablesanda,b,andcarefittedparameters.Themolecularweightandtheoctanol-waterpartitioncoefficientareexamplesof

4、moleculardescriptors.QSARtoxicitypredictionsmaybeusedtoscreenuntestedcompoundsinordertoestablishprioritiesforexpensiveandtime-consumingtraditionalbioassaysdesignedtoestablishtoxicitylevels.Whenconditionsdonotpermittraditionalbioassays,QSARsareanalternativetobioassaysforestimatingtoxicity.

5、InadditionQSARmodelsareusefulforestimatingtoxicitiesneededforgreenprocessdesignalgorithmssuchastheWasteReductionAlgorithm(http://www.epa.gov/nrmrl/std/cppb/war/sim_war.htm).TheToxicityEstimationSoftwareTool(T.E.S.T.)hasbeendevelopedtoallowuserstoeasilyestimatetoxicityusingavarietyofQSARme

6、thodologies.T.E.S.Tallowsausertoestimatetoxicitywithoutrequiringanyexternalprograms.Userscaninputachemicaltobeevaluatedbydrawingitinanincludedchemicalsketcherwindow,enteringastructuretextfile,orimportingitfromanincludeddatabaseofstructures.Onceachemicalhasbeenentered,itstoxicitycanbeestim

7、atedusingoneofseveraladvancedQSARmethodologies.Theprogram3doesnotrequiremoleculardescriptorsfromexternalsoftwarepackages(therequireddescriptorsarecalculatedwithinT.E.S.T.).1.1.ToxicityEndpointsT.E.S.Tallowsyoutoestimatethevalueforseveraltoxicityendpoints:1.96hourfat