enzymes proteins that act as biological catalysts proteins that act as biological catalysts...

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Enzymes Enzymes Proteins that act as biological Proteins that act as biological catalysts catalysts Substrates Substrates are molecules that an enzyme are molecules that an enzyme binds during a particular reaction binds during a particular reaction Catalysts- Catalysts- molecules that increase the molecules that increase the rate of a reaction without being used rate of a reaction without being used up in the reaction up in the reaction Enzymes are proteins so all the general Enzymes are proteins so all the general properties of proteins apply to enzymes properties of proteins apply to enzymes

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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.