Enzymes Flashcards
How do enzymes reduce activation energy
Correctly orients substrates
Strains substrate bonds
Proved a favorable micro environment (R groups)
Brief covalent bonds with substrate
What is an enzyme
Helps to lower Ea allowing reactions to proceed more efficiently
What is activation energy
Initial amount of energy needed for the reaction to proceed
What is the allosteric site
Site located away from the active duty where the non competitive inhibitor can fit
Where is the energy of ATP stored
In bonds between its terminal phosphate groups
Where are enzymes located
It can either be free in the cytoskeleton or be bound to membranes and organelles
What does free energy look like as the reaction progresses on a graph
Reactions without and enzyme have a higher Vmax than reactions with an enzyme, but they both meet at y=0
What does the graph of concentration substrate look like with and without inhibitors
Without an inhibitor the rate has a higher Km than with an inhibitor but they both have the same 1/2 Vmax and Vmax
What is the product of a reaction used for in feedback inhibition
The product directly inhibits the enzyme that made it
What happens when the acidity increases (H+)
The H+ is attracted to O, OH becomes an ion dipole (weak) and the molecule becomes more basic
What happens to enzymes when the temperature is decreased
The bonds are unable to move and are inflexible
What happens to enzymes when you increase the temperature
The energy increases causing the molecules to fall apart
During the catalytic cycle what happens to thermodynamics
The thermodynamics are unchanged throughout the catalytic cycle
How does feedback inhibition regulate enzymatic activity in the biochemical pathway
It can shut down the pathway if something goes wrong
What is feedback inhibition
A way to regulate enzymatic activity in the biochemical pathway
What is an example of a biochemical pathway
Glycolysis
What is a biochemical pathway
The product of a reaction becomes the substrate for the next reaction
What is the 1/2 Vmax
Half of the Vmax value
What is Km
The concentration substrate it takes to reach 1/2 Vmax
Is the reaction rate higher or lower without the inhibitor? With the inhibitor?
Without: the reaction rate is higher
With: the reaction rate is lower
How would you get rid of the competitive inhibitor
Add more substrate
What is the Vmax
The maximum reaction rate that can happen within that system
Does Ea have an effect on delta g
No matter what Ea is, delta G doesn’t change
What happens when substrate concentration increases
Reaction rate increases and eventually levels off
What is a michaelis menten plot
Shows substrate concentration vs reaction rates
What is a non competitive inhibitor
Bonds to the allosteric site which changed the shape of the active site
What is a competitive inhibitor
Mimics substrate and competes with the substrate for access to active site
What are inhibitors
Controls enzyme activity
What is normal binding
A substrate can normally bind to the active site of an enzyme
Why is Mg2+ essential for ATP hydrolysis
It brings substrates together which stabilized molecules
What are organic cofactors
Small, non-protein organic molecules (vitamins)
What are inorganic cofactors
Metallic ions that can move electrons from covalent bonds (Mg, zinc, copper, etc.)
Enzymes are…
Substrate specific, meaning they only react with specific substances
What is the 1st step of the catalytic cycle
Substrates enter the active site
What is the second step of the catalytic cycle
Substrates are held in the active site by weak interactions
What is the third step of the catalytic cycle
The active site lowers the Ea
What is the 4th step of the catalytic cycle
Substrates are converted into products
What is the 5th step of the catalytic cycle
The products are released
What stage of protein structure is the active site in
Quaternary structure
What does an increase of G cause during the catalytic cycle
Unstable transition state
Bonds break and new ones form
Free energy is released (spontaneous)
