5.1 Enzymes Flashcards
enzyme
biological catalyst
speeds up chemical reactions by reducing activation energy
substrate
reactant that binds to an enzyme
active site
where substrates bind to an enzyme
activation energy
amount of energy required for a chemical reaction to occur
reaction specific
each enzyme has specific substrates that can bind to it
not consumed in reactions
one enzyme can perform many reactions
affected by cellular conditions
enzymes are made of proteins and can be denatured by the same conditions (temperature, concentration of ions)
substrate concentration and reaction rate
more substrate = more successful collisions
eventually, enzymes become a limiting factor in reaction rate
enzyme concentration and reaction rate
more enzymes = more successful collisions
eventually, substrate becomes a limiting factor in reaction rate
temperature
higher temp = more successful collisions
to hot = enzyme denatures
optimal temperature (humans) = 37 Celsius
pH
too low/too high = enzyme denatures
optimal pH depends on environment (pepsin is in the stomach, a very acidic environment, and optimal pH is around 3. trypsin is in the small intestine, a basic environment, and its optimal pH is around 9. most are in neutral environments and their optimal pH is 7
How would you maximize enzyme activity considering all of the factors discussed in class? Minimize?
Maxime: increase enzyme and substrate concentration, optimize temperature and pH
Minimize: decrease enzyme and substrate concentration, un-optimize temperature and pH
Compare and contrast inhibition and activation of enzymes
Inhibition:
- competitive: inhibitor binds to active site to prevent substrate from binding
- noncompetitive: inhibitor binds to enzyme and changes shape of active site to prevent substrate from binding
Activation:
- activator binds to enzyme and changes shape of active site to allow substrate to bind
Both:
- noncompetitive inhibition and activation change shape of active site
