unit 6 enzymes Flashcards
enzymes usually have what structure
tertiary
reactants aka
substrates
intermediates are not
isolatable/purifiable
rate of rxn dependent on
[reactants] temperature ph activation E and the energy barrier [products] (like if reach equilibrium)
catalysts help
lower energy barrier/activation energy, would make rxn more likely to occur
forward and reverse reactions occur
simultaneously at diff rates
() rxn rate are faster
initial
equilibrium state
concentration of products cannot increase further, forward and reverse reactions still occurring but NO NET CHANGE
equilibrium constant Keq
[products]/[reactants]
Keq=k1 (forward rxn) /k-1 (reverse rxn)
how Keq calculated
from equilibrium concentrations or ratio of rate constants
activation energy (Ea or delta G*)
when two reactants collide A+B, energy is realeased.
Must be greater than the energy barrier for the reaction to proceed
energy barrier
amount of energy required for the formation of products
what represents the net difference of energy
delta G
start low energy and end at high means it
cost us energy
+delta g means
cost us energy and is endergonic
-delta g means
released energy exorgonic
high energy to low means
released energy -G
reaction rate/ velocity
how fast the products are formed.
when measure velocity
very early in rxn (before reverse rxn)
units for velocity
mole/sec, umol/min
free energy change delta G (gibbs free energy)
difference between initial free energy of the reactants and products
delta g ultimately determines the
final concentrations of reactants and products BUT NOT THE REACTION RATE
what actually affects rate
activation energy
what is delta G0
change in free energy from standard state, 1.0 M concentrations of substrates and products to equilibrium
standard state STP
25 degrees C (298K) 1 stm ph 7
If free energy of products is lower than subtrates thes signs of delta G0 will be
negative -
if free energy is higher than products/products it will be
positive +
-delta g will occur () although () is not known
spontaneously, rate
enzymes are 6 things
- catalysts
- protein
- ph and temperature dependent
- specific
- saturable
- inhibitors, stimulators
catalysts 4 key things
increase rate of reaction
are not consumed
bind to substrates (reactants), lower Ea
don’t change Keq