C4 Enzymes Flashcards
What are enzymes ?
Proteins with are biological catalysts and hence can speed up chemical and metabolic reactions by lowering the activation energy.
Facts about the active site:
- Binds to the substrate
-complementary to substrate shape (specific)
What are the two models for enzymes we need to know?
-lock and key model
-induced fit
What is the difference between the two models of enzymes we know?
- the first one is the lock and key theory which is where the enzyme will have a set active site and will somehow need to fit in the substrate , this is very rigid and requires perfect collisions which is very hard
- However, then the induced fit was suggested which is where the enzyme active site can change slightly to fit the substrate
What are intercellular enzymes ?
Intracellular enzymes are found inside cells and are responsible for processing food inside the cell
Example of an intercellular enzymes
Catalase
What is an extracellular enzyme?
Extracellular enzymes, on the other hand, are located outside of cells and are used to interact with other molecules outside of the cell
Examples of an extracellular enzyme
1) Amylase (starch to maltose)
2) Trypsis (protein to amino acids)
Factors that affect enzymes activity
1) Temperature
2) PH
3) Substrate/enzymes concentration
How does temperature affect enzyme activity
Kinetic energy increases, molecules move quicker , higher chance of the active site of the enzymes to and substate to collide with one another therefore increase the rate of reaction
In a enzyme temperature rate graph what are the different parts called
1- low temperature =enzymes are inactive, rate is slow, low kinetic temperature
2-optium temperature , maximum rate of reaction (vmax)
3- rate will drop, enzymes are denatured (loss of active site), active site is destroyed,
What is Q10 in enzymes?
The Q10 temperature coefficient is a measure of temperature sensitivity based on the chemical reactions.
Every 10 degrees
EG: Q10=2, every 10 degrees temperature will double…
How does PH become acidic or alkaline ?
Higher the PH, lower the H+ or Proton concentration, alkaline and vice versa
What are enzyme inhibitors?
The inhibitor molecule, which has a similar shape to the substrate molecule, competes with the substrate to bind to the active site of an enzyme
What are the two different sites on an enzyme?
-Active site (top)
-Allosteric site (bottom)
What is the difference between an active site and allosteric site?
Active site is at the top and that is where the substrate bind, allosteric site is where any other thing can bind and is at bottom
What are the two types of inhibitors?
-competitive-> Goes to the active site and compete with the substrate with the active site- the active site does not change shape
-non-competitive- binds to a site other than the active site, not competing for the active site, causes structural change to the active site
What does increasing substrate do to competition inhibition?
Competitive inhibition can be overcome by increasing the concentration of substrate as there will be a higher chance of collisions and the substrate will out number the completion inhibitors
Competition inhibitors have a similar structure to substrate hence they compete for the same active site. Less active sites available means less enzymes substrate complexes formed meaning less rate.
What does increasing substrate do to Non-competitive inhibition?
- doesent affect the rate
- Noncompetitive inhibition, however, cannot be easily overcome by substrate concentration because the inhibitor binds to a site other than the active site
-higher substrate can not restore VMAX
-the only way to restore the vmax is to remove the non competitive inhibitor
What are cofactors?
A cofactor is a non- protein chemical compound that is bound to a protein and is required for the protein’s biological activity
What are enzymes first called when they are produced and what do they mean?
Apoenzymes -inactive form of the enzyme , cant catalyse any enzyme , they then turn to holoenzyme , when they change the tertiary structure
How can we make a holoenzyme from an apoenzyme ?
-its is a increases in activation , basically is a change in tertiary (3D structure)
How do we activate an apoenzyme into a holoenzyme? (3)
1- use of another enzyme
2- change in surrounding condition (EG: Temp and PH)
3-Cofactors
What is the Q10 formula?
rate at higher temperature/rate at lower temperature
What does an reversible and non-reversible inhibitor do ?
A reversible inhibitor inactivates an enzyme through noncovalent, reversible interactions
An irreversible inhibitor inactivates an enzyme by bonding covalently to a particular group at the active site
Why are cofactors and coenzymes needed and examples of them
for oxidation-reduction reaction and group transfer processes which are not facilitated by functional groups of proteins.
Cofactors = chloride ion
Coenzyme = Amylase and vitamins
