Enzymes and inhibitors Flashcards
What are enzymes?
Biological catalysts which increase the rate of chemical reaction by lowering the activation energy of it
what is the active site?
the area of the enzyme where the substrates bind
What is the induced fit model?
When enzyme and substrate form complex, the structure is distorted so the active site moulds around the substrate
How do you measure the initial rate of reaction?
Calculate the gradient of a concentration-time graph at t=0
What factors affect the rate of enzyme controlled reactions?
Enzyme/substrate concentration, temperature and PH
Why will increasing enzyme/substrate concentration not always increase the rate of reaction?
Because the other variable will become a limiting factor meaning rate can’t increase any further
Why will rate decrease after the optimum temperature/PH is reached?
The enzyme will become denatured as hydrogen bonds are broken within the protein
What is an inhibitor?
Substances which stop enzyme binding to substrate, therefore controlling reaction
What is competitive inhibition?
Competes with substrate for binding to active site, preventing binding, reversible by increasing substrate concentration
What is non-competitive inhibition?
Binds to different part of enzyme, allosteric site, changing shape of enzyme. Irreversible as the substrate won’t fit, decrease in reaction rate
What is end-product inhibition?
End-product of a multi-step reaction may act as an inhibitor to the enzyme which catalyses the initial stage of the reaction
