BIOC2303 Flashcards
Define Kcat?
The turnover number, the number of times each enzyme site converts substrate to product per unit time. Expressed in the inverse of the time units of the Y axis.
Define Km?
The Michaelis-Menten Constant, has the same units as x. It is the substrate concentration to achieve a half-maximum enzyme velocity.
Define Et?
The concentration of enzyme catalytic sites. Units: concentration per time.
Define Vmax?
Maximum enzyme velocity, same units as Y.
On an inverse velocity vs. substrate graph what would the slope be?
Km/Vmax
On an inverse velocity vs. substrate graph what would the y-intercept be?
1/Vmax
On an inverse velocity vs. substrate graph what would the x-intercept be?
-1/Km
What is an inverse velocity vs. substrate graph called?
Lineweaver-Burk plot
Define Kd for a simple association reaction and it’s relation to Ka?
1/Ka = Kd = [R][L] / [R:L]
What is the Michaelis-Menten equation?
Vmax x [S] / Km + [S]
What does Kcat/Km measure?
The specificity/catalytic efficiency of an enzyme.
What do higher Kcat/Km values mean?
The better the enzyme works on the substrate (higher specificity) and the more efficient the enzyme is.
Give the equilibrium constant equation?
Keq= [A][B] / [AB]
Define Ki?
The concentration of inhibit which is required to decrease the maximal rate of the reaction to half of the inhibited value in the presents of low substrate concentration.
How can you find Ki on a graph?
Look at the point in which all of the lines cross on an inverse velocity vs. inhibitor concentration graph.