Post on 31-Dec-2015
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EnzymesEnzymes Proteins that act as biological catalystsProteins that act as biological catalysts
SubstratesSubstrates are molecules that an enzyme are molecules that an enzyme binds during a particular reactionbinds during a particular reaction
Catalysts-Catalysts- molecules that increase the rate molecules that increase the rate of a reaction without being used up in the of a reaction without being used up in the reactionreaction
Enzymes are proteins so all the general Enzymes are proteins so all the general properties of proteins apply to enzymesproperties of proteins apply to enzymes
Enzymes (cont’d)Enzymes (cont’d)
StructureStructure– Primary Structure- determined by amino Primary Structure- determined by amino
acidsacids– Secondary Structure- Secondary Structure- ββ-sheets and -sheets and αα--
heliceshelices– Tertiary Structure- composed of elements Tertiary Structure- composed of elements
of secondary structureof secondary structure Hydrogen bonding, Hydrophobic interactions, Hydrogen bonding, Hydrophobic interactions,
Ionic bonding and Covalent bondingIonic bonding and Covalent bonding
– Quaternary Structure- composed of Quaternary Structure- composed of multiple polypeptide chainsmultiple polypeptide chains
Enzymes (cont’d)Enzymes (cont’d) Enzymes promote particular Enzymes promote particular
reactionsreactions– Determined by its three dimensional Determined by its three dimensional
structurestructure– Specific substrate bindingSpecific substrate binding
Enzyme binds to substrate via the Enzyme binds to substrate via the active siteactive site– Active site has specific shape and Active site has specific shape and
chemical properties that allow it to chemical properties that allow it to promote a specific reactionpromote a specific reaction
Enzymes (cont’d)Enzymes (cont’d)
Factors that effect enzymesFactors that effect enzymes– pH and temperature- variations can lead pH and temperature- variations can lead
to altering of tertiary structure making it to altering of tertiary structure making it inactive; Most of the time is a permanent inactive; Most of the time is a permanent changechange
– Organic Solvents- disrupt hydrophobic Organic Solvents- disrupt hydrophobic bonds (involved in tertiary and bonds (involved in tertiary and quaternary structure); Reversiblequaternary structure); Reversible
– Inhibitors- Prevent enzyme from binding Inhibitors- Prevent enzyme from binding to substrateto substrate
– Protease- breaks down enzymeProtease- breaks down enzyme
Lab InfoLab Info Work in groups of 4Work in groups of 4
Only 1 person in each group will handle the Only 1 person in each group will handle the sodium azidesodium azide– Wear goggles and glovesWear goggles and gloves
Use the same hydrogen peroxide for every Use the same hydrogen peroxide for every reaction EXCEPT after the sodium azidereaction EXCEPT after the sodium azide– Dispose of hydrogen peroxide in waste containerDispose of hydrogen peroxide in waste container
Only have to do the control onceOnly have to do the control once– But make sure to include it on every graphBut make sure to include it on every graph
Label tube that will go in the incubator clearlyLabel tube that will go in the incubator clearly
Lab InfoLab Info Handle filter paper discs with tweezersHandle filter paper discs with tweezers
– Oil from your skin will alter reactionOil from your skin will alter reaction
Start timing as soon as the disk is in the hydrogen Start timing as soon as the disk is in the hydrogen peroxide and stop timing as soon as it reaches peroxide and stop timing as soon as it reaches the topthe top– Measure time to nearest 0.1 secondMeasure time to nearest 0.1 second
If the disk does not rise after 3 minutes assume If the disk does not rise after 3 minutes assume no reaction will occurno reaction will occur
Lab ReportLab Report Must be TYPEDMust be TYPED Should have 5 graphs (Bar Graphs)Should have 5 graphs (Bar Graphs)
– Graph the reciprocal time 1/T (Rate of Graph the reciprocal time 1/T (Rate of the reaction)the reaction)
– Graph the average of the runs of each Graph the average of the runs of each experimentexperiment
– Put error bars on the graphsPut error bars on the graphs– Graphs should contain a clear legendGraphs should contain a clear legend
States method of measurement and States method of measurement and identifies points and error barsidentifies points and error bars
– Look in lab manual for an exampleLook in lab manual for an example
Example of Data Table For Lab Example of Data Table For Lab ReportReport
Trial Trial 11
Trial Trial 22
Trial Trial 33
AveraAveragege
StandarStandardd DeviatioDeviation n
StandarStandard d ErrorError
ControlControl
Concentration Concentration 11
Concentration Concentration 22
Concentration Concentration 33
AssignmentsAssignments All lab reports must be typed All lab reports must be typed Do the lab report as follows- differs from Do the lab report as follows- differs from
lab manuallab manual– IntroIntro: Short background about the lab; include : Short background about the lab; include
hypothesishypothesis– Materials and MethodsMaterials and Methods: Summarize briefly; : Summarize briefly;
don’t need exactsdon’t need exacts– ResultsResults: tables/graphs of data and text to : tables/graphs of data and text to
summarize what they showsummarize what they show– DiscussionDiscussion: analysis of results; troubleshoot lab : analysis of results; troubleshoot lab
if it didn’t workif it didn’t work– ConclusionConclusion: short summary of everything : short summary of everything
All assignments are due at the beginning All assignments are due at the beginning of the next lab.of the next lab.
Order of ExperimentOrder of Experiment1.1. Start Trypsin reactionStart Trypsin reaction2.2. Run Control discRun Control disc3.3. Effect of concentrationEffect of concentration
– Run [100%], [50%], Run [100%], [50%], [25%] 3 times each[25%] 3 times each
4.4. Effect of temperatureEffect of temperature– Run boiled, room Run boiled, room
temperature, and temperature, and iced samples 3 iced samples 3 times eachtimes each
4.4. Effect of pHEffect of pH– Run pH 3, 5, 7, 9 Run pH 3, 5, 7, 9
three times eachthree times each
4.4. Effect of ProteasesEffect of Proteases– Run Trypsin sample Run Trypsin sample
3 times each (must 3 times each (must incubate ~1 hour)incubate ~1 hour)
5.5. Effect of InhibitorEffect of Inhibitor– Run Sodium Azide Run Sodium Azide
sample 3 times sample 3 times each.each.
– Dispose of h202 in Dispose of h202 in waste container.waste container.