1. proteins enzymes are specialized proteins catalysts act as catalysts to accelerate a reaction ...
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Enzymes are specialized ProteinsProteins
Act as CatalystsCatalysts to accelerate a reaction
Not permanentlyNot permanently changed in the process
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Are specific for what they will catalyzecatalyze
Are ReusableReusableEnd in –asease-Sucrase-Sucrase-Lactase-Lactase-Maltase-Maltase
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Enzymes work by weakening weakening bondsbonds which which lowers lowers activation activation energyenergy
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FreeEnergy
Progress of the reaction
Reactants
Products
Free energy of activationFree energy of activation
Without Enzyme
With Enzyme
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The substancesubstance (reactant) an enzymeenzyme acts on is the substratesubstrate
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EnzymeSubstrate Joins
A restricted regionrestricted region of an enzymeenzyme molecule which bindsbinds to the substratesubstrate.
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EnzymeSubstrate
Active Site
A change in the shapeshape of an enzyme’s active site
Induced Induced by the substrate
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A changechange in the configurationconfiguration of an enzyme’s activeenzyme’s active site site (H+ and ionic bonds are involved).
InducedInduced by the substratesubstrate..
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Enzyme
Active Sitesubstrate
induced fit
Three factors:Three factors:1.1. Environmental ConditionsEnvironmental Conditions
2.2. Cofactors and CoenzymesCofactors and Coenzymes
3.3. Enzyme InhibitorsEnzyme Inhibitors
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1. Extreme1. Extreme temperatures temperatures are the are the most dangerousmost dangerous- - high tempshigh temps may denature denature (unfold) (unfold) the enzyme. enzyme.
2.2. pHpH (most like 6 - 8 pH near (most like 6 - 8 pH near neutral)neutral)3.3. Substrate concentration- Substrate concentration- increasing substrate increases increasing substrate increases enzyme activity until levels are enzyme activity until levels are the same.the same.
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Inorganic substances Inorganic substances (zinc, iron)(zinc, iron) and vitaminsvitamins (respectively) are sometimes needed for proper enzymatic activityenzymatic activity.
Example:Example:IronIron must be present in the
quaternary quaternary structurestructure -- hemoglobinhemoglobin in order for it to pick up oxygen.pick up oxygen.
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a. a. Competitive inhibitorsCompetitive inhibitors:: are chemicals that resembleresemble an enzyme’s normal substrate enzyme’s normal substrate and competecompete with it for the active siteactive site.
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Enzyme
Competitive inhibitor
Substrate
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b. b. Noncompetitive inhibitorsNoncompetitive inhibitors::Inhibitors that do not enter thedo not enter the
active siteactive site, but bind tobind to another another partpart of theof the enzymeenzyme causing the enzymeenzyme to change its shapechange its shape, which in turn alters the alters the active siteactive site.
Enzymeactive site altered
NoncompetitiveInhibitor
Substrate