Lecture 13: Kinetics Flashcards
Competitive inhibition effects on Vmax and Km
Vmax stays the same
Km is increased
Uncompetitive inhibition effects on Vmax and Km
Vmax is reduced
Km is reduced
Noncompetitive inhibition effects on Vmax and Km
Vmax is reduced
Km stays the same
Km definition
[S] where reaction rate is half maximal
Half of the active sites are full
Vmax definition
Maximum rate possible for a given concentration of enzyme
Kcat definition
Turnover number
Number of substrate molecules converted per active site per time
Ks definition
A dissociation constant for substrate binding
Kcat/Km
Specificity constant
Measure of enzyme performance by predicting the fate of E S
Michaelis-Menten equation
V0 = Vmax*[S] / Km + [S]
V0 when [S] «_space;Km
V0 = (Vmax / Km)*[S]
V0 when [S] = Km
V0 = Vmax / 2
V0 when [S]»_space; Km
V0 = Vmax
Kcat of a good enzyme would be
Kcat»_space; K-1
Kcat/Km =~ K1
Kcat of a bad enzyme would be
Kcat «_space;K-1
Kcat/Km =~ 1/Km
Multiple binding site enzymes can follow Michaelis-Menten kinetics, as long as they are
Noncooperative
Y and X intercepts and slope of double reciprocal (Lineweaver-Burk) plot
Y intercept = 1/Vmax
X intercept = -1/Km
Slope = Km/Vmax
Group specific inhibitors do what, specificity
Target specific amino acid
Low specificity for active site
Substrate analog inhibitors do what, specificity
Substrate mimic, modify enzyme
High specificity for active site
Suicide inhibitors do what, specificity
Substrate mimic, unable to form products
Very high specificity for active site
