Enzymes Flashcards
(14 cards)
what is the role of enzymes?
biological catalysts
they lower the activation energy required for the reaction to occur.
describe intracellular and extracellular enzymes
intracellular: within cells e.g catalase breaking H2O2
extracellular: outside cells e.g amylase breaking starch in mouth
lock and key Vs induced fit
- Lock and Key: Enzyme’s active site is a perfect fit for the substrate.
- Induced Fit: Active site changes shape slightly to fit the substrate better.
How does pH affect enzyme activity?
Too high/low → changes shape of active site → denaturation.
effect of temp on enzyme ROR?
Higher temp → more kinetic energy → up to optimum, then denatures at high temp
How does enzyme concentration affect enzyme activity?
More enzymes = more A-S = faster rate (until substrate is limiting).
How does substrate concentration affect enzyme activity?
- More substrate = more collisions = more enzyme-substrate complexes = faster rate
- up until a certain point bcs les AS available so enzyme conc. becomes LF
what are coenzymes?
Organic molecules that assist enzymes (e.g., vitamins, NAD,NADP etc).
what are cofactors?
Non-protein helpers for enzymes (e.g., Cl⁻ for amylase)
what is a competitive inhibitor?
Similar shape to substrate, binds to active site, can be overcome by more substrate.
what is a non-competitive inhibitor?
Binds to allosteric site, changes enzyme shape, not overcome by more substrate.
what is end-product inhibition?
Final product of a reaction inhibits earlier enzyme → prevents overproduction.
reversible inhibitor?
- Temporary binding, enzyme can function again when inhibitor leaves.
- competitive inhibitors can be stopped if conc. of substrate inc and it outcompetes it
irreversible inhibitor?
- Permanent binding, enzyme permanently inactivated.
- non-competitive inhibiton bcs the AS is fully changed and substrate will never bind even if the conc. increases
