Enzymes Flashcards
Biological molecules - topic 1
What are enzymes
- Biological catalysts regulating biological processes in living organisms.
- Globular proteins
- Tertiary structure proteins
What determines function of an enzyme
Protein nature and tertiary nature
What do enzymes catalyse and why are they important
- Enzymes catalyse wide range of intracellular and extracellular reactions.
- These reactions determine structures and functions of cells
What is the shape of an active site
- Unique and specific
- because of the specific folding and bonding in the tertiary structure of a protein.
- enzymes can only attach to substrates that are complementary in shape due to specific active site.
lowering the activation energy
- All reactions require a certain amount of energy before they occur.
- When enzymes attach to the substrate, they can lower the activation energy to increase th erate of reaction (speed)
What does the lock and key model suggest
Enzymes are like a lock and substrates are like a key that fits due to its complimentary shape
What happens in the lock and key model
1) Enzyme substrate forms
- Enzyme active site is a FIXED shape
- Due to random collisions, subsrates collide and attach to enzymes which forms substrate complex
2) Lower the activation energy
- once enzyme substrate complex form charged groups
- substrate will distort the shape
- distortion will lower activation energy
3) Products will be released
- enzyme’s active site will be empty and ready to be reused
What does the induced fit model suggest
- enzyme is like a glove
- substrate is like your hand.
- glove isn’t exactly complimentary to your hands but the glove will mould around your hands and become complementary
What happens in the induced fit model
1) Enzymes active site is flexible and can slightly change
- Enzyme substrate complex occurs
- due to enzyme moulding around the substrate, it puts a strain on the bond which
2) lowers the activation energy
3) Products released and enzyme active site returns to original shape
