enzymes Flashcards
what is an allosteric inhibitor?
A small molecule that decreases the activity of an enzyme by binding to a site other than the catalytic site
why are enzymes are potent catalysts?
they lower the activation energy for the reactions they catalyse
why do enzymes differ from other catalysts?
enzymes display specificity toward a single reactant
what happens in competitive inhibition?
inhibitor binds reversibly at the active site
One of the enzymes involved in glucose metabolism, aldolase, requires Zn 2+ for catalysis. Under conditions of zinc deficiency, when the enzyme may lack zinc, it would be referred to as the ____________
apoenzyme
what is the concept of “induced fit”?
substrate binding may induce a conformational change in the enzyme, which then brings catalytic groups into proper orientation
what is the role of an enzyme in an enzyme-catalysed reaction?
to increase the rate at which substrate is converted into product
What is the definition of Km, the Michaelis constant?
The concentration of substrate at which the enzyme is operating at half its maximal velocity
which characteristic of V0 versus [S] for an enzyme that follows Michaelis-Menten kinetic
As [S] increases, the initial velocity of reaction V0 also increases.
The y-axis is a rate term with units of µM/min.
Km is the [S] at which V0 = 1/2 Vmax.
The shape of the curve is a hyperbola.
what happens after enzyme reaction?
the enzyme involved becomes available to catalyse the reaction again
what happens when temperature is lowered?
lower the reaction rate.
what do enzyme catalysts do?
They can increase the reaction rate for a given reaction by a thousand-fold or more.
