Lecture 13: Kinetics Flashcards
how is zero order reactions interpreted when substrate independent?
unimolecular reaction
enzyme is saturated
define Ka
association constant (make P) Ka= [P]/ [S]
Define Kd
dissociation constant (unmake P) Kd= [S] / [P] = 1/ Ka
Michaelis-Menten enzymes follow _______ order kinetics, but no matter what catalysis is not a _____ order reaction
first; first
Define Km
Michaelis constant
[S] where reaction rate is half maximal OR half of the active sites are full
Define Vmax
maximum velocity
maximum rate possible for a given concentration of enzyme
Define Kcat
turnover number
number of substrate molecules converted per active site per time (first order rate constant)
define Ks
a dissociation constant for substrate binding
define Kcat/ Km
specificity constant
measure of enzyme performances by predicting the fate of E*S
When is Vmax reached?
when the enzyme is fully saturated, [ES]= [E]T and rate equation is Vmax= Kcat[E]T
What is the Michaelis- Menten equation?
Vo= Vmax [S] / Km + [S]
What does Vo equal when [S] «_space;Km
= (Vmax/Km) [S]
What does Vo equal when [S] =Km
= Vmax/2
What does Vo equal when [S]» Km
=Vmax
A ______ enzyme would have Kcat»_space; K-1 and Kcat/Km = k1
good
A ______ enzyme would have Kcat «_space;K-1 and Kcat/Km = 1/Km
poor
What do group specific irreversible inhibitors do?
target a specific amino acid
What is the specificity for active site for group specific irreversible inhibitors?
low
What do substrate analogs do?
substrate mimic, modifies enzyme
What is the specificity for active site for substrate analogs?
high
What do suicide inhibitors do?
substrate mimic
unable to form products
What is the specificity for active site in suicide inhibitors
very high
