2.4 enzymes Flashcards
Definition of an intracellular enzyme
they are produced and function inside the cell
Definition of an extracellular enzyme
secreted by cells and catalyse reactions outside of the cell
Induced fit hypothesis
- the enzyme and the active site change shape slightly as the substrate molecules begins to enter the enzyme
- these changes are known as conformational changes
- they ensure an ideal binding arrangement is achieved
- this maximises the ability of it to catalyse reactions
Why at high levels of pH do enzymes become denatured?
- hydrogen and ionic bonds hold together the tertiary structure of the protein together
- below or above optimum pH an excess of H+ ions or OH- ions can build up causing the bonds to break
- the broken bonds change the shape of the active site so eventually enzyme substrate complex’s can no longer form
Why are buffer solutions used in experiments
- they maintain a specific pH even if the reaction would otherwise change the pH
What is the temperature coefficient
the ratio between the rates of that reaction at two different temperatures
Equation for the temperature coefficient
Q10= rate of reaction at x+10 / rate of reaction at x
What is a competitive inhibitor
they have a similar shape to that of the substrate molecule
What is a non-competitive inhibitor
bind to the allosteric site which alters the shape of the active site preventing the substrate from binding to it
How to reverse increased competitive inhibitor concentration
increasing the substrate concentration as that means they are more likely to collide with enzymes
How to reverse increased non-competitive inhibitor concentration
increasing substrate concentration will NOT do anything as the active site has already changed shape
Process of end-product inhibition
- as the enzymes convert the substrate into product, the process is slowed down as the end-product of the reaction chain binds to an allosteric site
- the end product can then detach and be used elsewhere allowing the active site to reform
- this means as the product falls the enzyme catalyses the reaction once again in a CONSTANT FEEDBACK LOOP
How to inhibitors form irreversible reactions
form covalent bonds with the enzymes
Why are irreversible inhibitors dangerous
their biological reaction the enzyme is catalysing will be completely stopped
Definition of cofactor
inorganic ions that an enzyme needs in order to function
minerals
non-protein