Anabolism vs Catabolism What is necessary for a chemical reaction to begin Reactants must come together in the right orientation With enough energy So ho do enzymes catalyze this process Lowers activation energy ID: 913672
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Slide1
Metabolism
Slide2Enzymes: review
Slide3Anabolism vs Catabolism
Slide4Slide5What is necessary for a chemical reaction to begin?
Slide6Reactant(s) must come together in the right orientation
With enough energy
So ho do enzymes catalyze this process?
Slide7Slide8Lowers activation energy
Template for proper orientation of substrates
As active site “holds” substrate – can stress/strain the substrate, breaking bonds
More conducive
microenvrionments
–
ie
altering pH
Slide9Slide10Slide11Slide12Slide13Enzyme specificity
What contributes to it?
Slide14Complementary fit
Slide15Lock and Key Model
Slide16Induced Fit Model (replaces lock and key)
Enzymes = globular proteins
Shape shifters – subtle
Active site is not rigid
Can fit more snugly around substrate
Slide17Catalysis
Saturation – limiting factor = max enzymatic rate
Slide18Enzyme efficiency
Determined by environmental factors
Optimal conditions
Slide19Cofactors
Nonprotein
helpers
Zinc, iron, copper
Vary in how they bind to enzyme
Perform a critical function in catalysis
Slide20coenzymes
Organic cofactors
Most vitamins
Slide21Other factors influencing reaction rate…
inhibitors
Reversibility
Slide22Competitive inhibition
Slide23Noncompetitive inhibition
Slide24examples
Sarin
: nerve gas
DDT and parathion
antibiotics
Slide25Regulation
Selective inhibition
Cells control when and where enzymes are active
control the building of the protein
Control the protein once its built
Slide26Allosteric regulation
Protein function at one site is affected by the binding of a regulatory molecule to a separate site
Can inhibit or stimulate