5/6- Enzymes I & II Flashcards
what is an enzyme?
a protein catalyst for specific biochemical reactions
what does an enzyme affect?
they speed up reactions by lowering the activation energy of a reaction
what does an enzyme not affect?
Keq and deltaG are not affected by enzymes
name 2 models used to describe enzyme specificty and/or catalytic activity
the lock and key model and the induced fit model
what is a prosthetic group?
non-protein organic molecule that tighly binds to the enzyme’s active site; when prosthetic group is attached, an apoenzyme becomes a holoenzyme
name the 6 classes of enzymes
- oxidoreductases, 2. transferases, 3. hydrolases. 4. lyases, 5. isomerases, 6. ligases
what is the michaelis menton equation and what do the terms mean?
V=Vmax[S]/(Km+[S]) Km = constant value for specific substrate Vmax = maximum velocity of rxn [S] = substrate reaction V = velocity of reaction
in an MM plot, where is Vmax and how do you find Km?
Vmax is found when [S] is very high ; Km is determined by finding [S] when V = 1/2 Vmax
A lineweaver-burk plot is also called a _________ ______ plot.
double-reciprocal plot
what are the vertical and horizontal intercepts of the lineweaver-burk plot
vertical = 1/Vmax; horizontal = 1/Km
what are the advantages of the eadie-hofstree plot?
the EH plot is more advantageous because it will give more evenly spaced data points; not clustered like the LB plot
what distinguishes a competitor inhibitor from the rest?
they bind directly to the active site; they can be overcome by increasing [S]
what does the inhibitor bind with for competitive inhibition?
competitive = active site
what does the inhibitor bind with for non competitive inhibition?
non competitive = react w/ enzyme to reduce its effectiveness to bind with substrate
what does the inhibitor bind with for uncompetitive inhibition?
uncompetitive = bind with the ES complex (irreversible)
