enzymes Flashcards
catalyst
substance that can change the rate of a reaction without being altered in the process
enzyme
biological catalyst
Speeds up metabolic reactions by lowering the activation energy
activation energy
energy needed to start reaction
enzyme often ends in
-ase
enzymes are in the form of
proteins
do enzymes affect the change in free energy? how
no
they speed up reactions that would occur eventually
substrate
The reactant that an enzyme acts on
when is an enzyme-substrate complex formed
when The enzyme binds to its substrate
active site
the region on the enzyme where the substrate binds
where does a substrate bind to in an enzymatic reaction
active site
how does the active site lower the activation energy barrier (4 ways)
Orienting substrates correctly
Straining substrate bonds
Providing a favorable microenvironment
Covalently bonding to the substrate
substrate binding process (6 steps)
- substrates enter active site
- substrates held in active site by weak interactions
- active site can lower activation energy and speed up a reaction
- substrates are converted into products
- products are released
- active site is available for two new substrate molecules
induced fit
ENZYME FITS SNUGLY AROUND SUBSTRATE – “CLASPING HANDSHAKE”
an enzyme’s activity can be affected by:
temperature
pH
chemicals
cofactors
non-protein enzyme helpers such as minerals (eg. Zn, Fe, Cu)
