Enzymes Flashcards
Enzyme + type of protein
Biological catalysts that interact with substrate molecules to facilitate reactions.
Globular proteins
Substrate
A substance used or acted on by another process or substance.
A reactant in an enzyme-catalyzed reaction.
Complementary to the active site
Product
The final substance formed from the reaction facilitated by the enzyme.
Why are enzymes necessary to life
Enzymes help catalyze important reactions in metabolic pathways essential for life.
Anabolic reactions
Reactions that require energy that form larger, more complex molecules from smaller molecules.
Catabolic reactions
The breaking apart of molecules into smaller molecules to release energy
Digestion
The breaking down of chemicals in the body to a form that can be absorbed and used.
Metabolism
The sum of the chemical reactions that take place within each cell of a living organism and that provide energy for vital processes and for synthesizing new organic material.
Intracellular enzyme
Enzymes that act within cells: very sensitive to factors of rate of reaction.
Extracellular enzyme
Enzymes released from cells to break down these large (nutrient) molecules into smaller molecules that are taken in ie. for digestion.
Examples of intracellular enzyme
Catalase
Examples of extracellular enzyme
Amylase, Trypsin
Substrate and Product of Catalase
Catalyzes the decomposition of hydrogen peroxide to water and oxygen
Substrate and Product of Amylase
Amylose to Maltose
Substrate and Product of Trypsin.
Proteins to smaller peptides
Active site
Area of an enzyme with a shape complementary to a specific substrate, allowing the enzyme to bind with said substrate.
Enzymes only work for one specific substrate as
The active site is specific to only the substrate that is complimentary to the enzyme’s active site.
Lock and Key Hypothesis
Like a lock and a key, only a specific substrate will fit the active site of an enzyme.
Induced-fit hypothesis
When a substrate molecule collides with an enzyme, if its composition is specifically correct, the shape of the enzyme’s Active Site will change so that the substrate fits into it and an Enzyme-Substrate Complex can form.
The protein structures involved in making the shape of the active site
Tertiary structure
Activation Energy
The energy required to initiate a reaction
Rate of Reaction
The measure of how quickly it takes for an enzyme to convert all substrate into its products.
Enzyme ____ Activation Energy
Reduces
Factors Affecting the Rate of Reaction
Temperature
pH
Substrate Concentration
Enzyme Concentration
Temperature and Enzymes
Higher temp= more kinetic energy More collisions of substrate and active site more ES complex formed After optimum, temperature effects 3o The active site is changed
Temperature coefficient (Q10)
The measure of how much the r.o.r increases with a 10C temp. increase.
Usually 2 for enzyme controlled reaction
Explain why Siamese cats are white with black tails, ears, paws, and faces.
The black fur helps conserve more heat in the extremities and so allows for the optimum temperature for enzymes.
Why are enzymes so sensitive to pH
A slight change affects H bonds/ R groups ie. ionic bonds in 3o
Substrate conc. and Enymes
Higher substrate conc. means more chance of active sites colliding with substrates.
More ES complexes formed
Until all substrates turned into products/Vmax
Enzyme conc. and Enzymes
Higher enzyme conc. means more active sites colliding with substrates (higher chance).
More ES complexes formed
Until Vmax
Vmax
Maximum initial velocity/rate of reaction of an enzyme
co-factor/co-enzyme
Non-protein components that are necessary for the effective functioning of an enzyme.
prosthetic group
Non-protein (metal ion) component of a conjugated protein.
Enzyme inhibitor
Reduce the rate of an enzyme-catalyzed reaction by interfering with the enzyme in some way. This effect may be permanent or temporary.
Competitive inhibitor
An inhibitor that competes with substrates to bind to an active site.
Still makes sure enzymes are re-usable so it does not affect V max.
reversible inhibitor
Non-competitive inhibitor
An inhibitor that binds to the allosteric site of an enzyme, changing the shape of the active site.
Affects overall v-max.
Irreversible enzyme as the change of enzyme active site cannot be reversed
Allosteric site
A site that allows molecules to inhibit enzyme activity by changing its active site shape. It’s different than the active site on an enzyme, where substrates bind.
End Product Inhibition
The product of a reaction inhibits the enzyme required for the reaction.
