温度对酶活性的影响enzyme activityppt课件.ppt

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1、2)a)Theeffectsoftemperature,ontheenzymeactivityNextBiochemistryPracticalInvestigatetheeffectoftemperatureonamylaseactivity1Materialsrequired1.Waterbath2.Stirrer3.LaboratoryThermometer4.Beaker5.Measuringcylinder6.Boilingtube7.Stopwatch8.Starchsolution(2

2、mg/ml)9.Amylasesolution(0.5mg/ml)10.Potassiumiodide(I2-KI)solution11.Benedict’ssolution2ProdedureStep1Setupfivewaterbathsatdifferenttemperatures,e.g.0°C,28°C,37°C,55°C,80°C.28°C37°C3Step2Intoeachoffiveboilingtubesput5mlstarchsolutionand3dropspotassium

3、iodide(I2-KI)solution.4Step3Intoeachoffivemoreboilingtubesput2mlamylasesolution.5Step4Placeapairofboilingtubesintoeachwaterbathandleavefor5minutes.28°C37°C6Step5Pourtheamylaseintothetubeofstarchsolutionandgentlyshake.Repeatforeachtemperature.7Step6Repl

4、acethetubesinthewaterbathandmeasurethetimetakenfortheblue/blackcolourtodisappear.28°C37°C8Step7Testforsugar:add1mlBenedict’ssolutiontoeachboilingtubeandheatfor5minutes.9Step8Abrickredcolourindicatesareducingsugarispresent.10Step9Repeatthewholeexperimen

5、twithboiledamylaseasacontrol.11ExpectedresultTheenzymeworksbestat37OC.Theblue/blackcolourfadedandBenedict’sresultedinapositivetest.12TableofResultsTemperature(°C)TimetakenforsolutiontoturncolourlessTestforsugar13PrincipleofBenedict’stestBenedict'sreage

6、ntisusedasatestforthepresenceof reducingsugars.Thisincludesall monosaccharides andmany disaccharides,including lactose and maltose.Benedict'sreagentcontainsbluecopper(II)ions(Cu2+)whicharereducedtocopper(I)ions(Cu+).Theseare precipitated asred copper(I

7、)oxide whichisinsolubleinwater.Benedict'sReagentprovidesasemiquantitativetestforreducingsugarsalongwithqualitativetest.Thecoloroftheobtainedprecipitategivesanideaaboutthequantityofsugarpresentinthesolution.Agreenishprecipitateindicatesabout0.5%concentr

8、ation;yellowprecipitateindicates1%concentration;orangeindicates1.5%andredindicates2%orhigherconcentration.142)b)TheeffectsofpH,ontheenzymeactivityNextPresentedbyDr.A.K.M.ArifUddinAhmed.Lecturer,DepartmentofPharmacology&Biochemistry.Medi