Write out the rate law equations for each association/dissocia...

Question

Write out the rate law equations for each association/dissociation indicated below.

a) Rate law for ES dissociation into E + P: V = ______________

b) Rate law for E + S association: V = ______________

c) Rate law for ES dissociation back into E + S: V = ______________

Accepted Answer

Alright. So this practice problem wants us to write out the rate law equations for each association and each dissociation indicated below in this enzyme catalyzed reaction. Now, notice again that in this enzyme catalyzed reaction, we're missing the reverse reaction here for k minus 2, and because k minus 2 is negligible and not being considered here, we know that this enzyme catalyzed reaction is occurring very, very early on at the very beginning of our reaction, and so it's essentially the initial, enzyme catalyzed reaction. And so looking at our first one here, the rate law for the enzyme substrate complex dissociation into the enzyme and product, notice that this is literally just the enzyme substrate complex dissociating forwards into the free enzyme and the free product. And this rate law, we already did in our last lesson video. And so it's essentially the rate law that includes k2. And so we know that the rate laws are literally just going to be the reaction velocities times the rate constants, and the rate constant for this particular reaction is gonna be k 2 times the concentration of the reactant, and the reactant for this particular reaction right here is gonna be the enzyme substrate complex. And so, we can go ahead and put that in here, the reactant times the enzyme substrate complex. And then of course we're in our course, we're going to assume that the coefficients reaction orders. And so, we can say that the reaction order is just going to be 1. And so this right here is the rate law for the product formation step right here. And, essentially, that is the same thing as the enzyme substrate dissociation into enzyme and product. So now moving on to the next rate law, what we have is the rate law for the enzyme and the substrate association. And so if the enzyme and the substrate are associating together, that's gonna be this forward rate constant to form the enzyme substrate complex, and that is indicated by k one. And so we can say that the reaction velocity, the rate law will be the reaction velocity times the rate constant k1 times the reactant concentration. And so, notice that k1 actually has 2 reactants in the reaction. It has the enzyme and the substrate separately, and so we can put the concentration of our first reactant raised to the order, and the order is again going to be the coefficient, so it'll just be 1. And then times the reactant concentration of our second reactant which will be the substrate, and so we can put that in as well. And of course, the coefficient is 1 in front, so we can put that up above as well. And so this is going to be the rate law expression for the enzyme and substrate association together, essentially this forward reaction right here. And then, of course, this last option c here is the rate law for the enzyme substrate complex dissociation backwards into the free enzyme and the substrate. So essentially starting with the enzyme substrate complex and dissociating backwards into the free enzyme and the, free substrate. And so this is going the rate law will be the reaction velocity v, which is equal to the rate constant, and for this reverse reaction it will be k minus 1, so it'll be k minus 1, times the concentration of the reactant. And the reactant for this reverse reaction going backwards is actually gonna be the enzyme substrate complex. And so we can put that in here, enzyme substrate complex. And again, the reaction order is going to be the coefficient which is going to be 1. And so this here is the rate law expression for the enzyme substrate complex dissociation backwards into the expression for the enzyme substrate complex dissociation backwards into the enzyme and substrate. And so, essentially, these here are our answers to our practice problem, and that concludes this practice problem. And these are all alternate ways to express the reaction velocity for each of these, reactions that occur within our enzyme catalyzed reaction. So important to be able to apply this moving forward. And that concludes this practice. I'll see you guys in our next video.

Struggling with Biochemistry?

Write out the rate law equations for each association/dissociation indicated below.

a) Rate law for ES dissociation into E + P: V =
b) Rate law for E + S association: V =
c) Rate law for ES dissociation back into E + S: V = __

Watch next

Rate Constants and Rate Law practice set

Struggling with Biochemistry?

Write out the rate law equations for each association/dissociation indicated below.a) Rate law for ES dissociation into E + P: V = ______________b) Rate law for E + S association: V = ______________c) Rate law for ES dissociation back into E + S: V = ______________

Watch next

Rate Constants and Rate Law practice set

Write out the rate law equations for each association/dissociation indicated below.

a) Rate law for ES dissociation into E + P: V =
b) Rate law for E + S association: V =
c) Rate law for ES dissociation back into E + S: V = __