| What happens in non-competitive inhibition? (4) | inhibitor binds to allosteric site = changes the shape of the active site
indirectly blocks reaction
effects cant be lowered by increasing substrate |
| What is metabolism? | sum of all anabolic and catabolic reactions to maintain life |
| How do enzymes affect activation energy? | lowers EA = Speeds up rate of reaction |
| What is catabolism? what type of reaction is it? | breaks down molecules bonds = releases energy = exergonic |
| What is anabolism? What type of reaction is it? | forms molecule bonds = needs energy = endergonic |
| What is an enzyme inhibitor? | prevents substrate-enzyme complex forming |
| How is a substrate-enzyme complex formed? (4) | conformational change to active site = induced fit model
specific and complementary
destabilises bond in substrate
lowers activation energy |
| What happens in competitive inhibition? how can effects be lowered? (3) | inhibitor binds to active site = structurally + chemically similar to substrate
directly blocks reaction
effects can be lowered if substrate conc increases |
| What happens in non-competitive inhibition? (4) | inhibitor binds to allosteric site = changes the shape of the active site
indirectly blocks reaction
effects cant be lowered by increasing substrate |
| What is an example of competitive inhibition? how does it work? (5) | Relenza - treatment for influenza
binds to neuraminidase active site
prevents cleavage of docking proteins
prevents virons releasing from infected cells = prevents spread |
| What is an example of non-competitive inhibition? (4) | cyanide binds to cytochrome oxidase complex (IV)
changes active site = electrons cant release with oxygen = ETC shuts down
ATP production shuts down = death |
| What is the allosteric site? | place on enzyme where an inhibitor can bind, which changes active site |
| What is feedback inhibition? | final product in a series inhibits an enzyme from an earlier step by binding to allosteric site to control the amount of product made
negative feedback loop |
| What is an example of end product inhibition? (4) | threonine = isoleucine (amino acid)
in plants and bacteria
first converted into intermediate w threonine deaminase
isoleucine binds to allosteric site (non-competitive)
excess isoleucine prevents further production |
| What is the effect of inhibition on enzyme kinetics? | non-competitive < competitive <uninhibited |
