Flashcards in Allosteric Enzymes Deck (18):
Allosteric enzymes usually display ___ cooperatively with their substrate
In regards to allosteric enzymes, the binding of one substrate molecule facilitates....
the binding of subsequent molecules to the enzyme
Allosteric enzyme has more than one ___ ___ site
v = Vm[S]^n / K0.5 + [S]^n
What is this equation's name?
the hill equation
The Hill number (n) is a measure of the degree of ___
The larger the value of n, the greater the cooperativity, and the greater the ____ of the curve
If n = 1, describe the cooperativity
there is none
Explain the difference between K0.5 and Km since both represent [S] at 1/2 Vmax
since the rate constants for an allosteric enzyme are different than those for a michaelis-menten enzyme, the two constants are not equal
Enzymes with positive cooperative kinetics have a more ___ range of activity response to [S] and act more like a "___"
Allosteric enzymes may be in a "tense" or "relaxed" conformation. At low [S], the enzyme is in the ____ conformation. Binding of [S} promotes a conformation change to the ____ conformation
note: tense is inactive, relaxed is active
The binding of S to an allosteric enzyme, which increases the affinity of the other catalytic sites for S is an example of ____ regulation
True or false? Homotropic regulation is almost always negative
Hetertropic regulation - describe
a regulatory molecule distinct from the substrate which binds to a site other than the catalytic site and modulates the activity of the enzyme
Heterotropic effectors interact with a site other than the active site. They can have a ___ or a ___ effect.
postive or negative
In regards to heterotropic effectors, what do V-system effectors do?
the effectors may affect the catalytic rate, and thus influence the Vmax - can be positive or negative
In regards to heterotropic effectors, what do K-system effectors do?
effectors affect the binding of substrate and thus influence the K0.5 - can be positive or negative
Describe what V-system effectors look like on a plot
Positive or negative lines star off with uninhibited line and then as the slope increases, the V-system effectors go higher or lower but maintain the same sigmoidal curve