Lineweaver-Burk Plot for Irreversible Inhibitors?

[aalamruad]

Advertisement - Members don't see this ad

I can't seem to find any Lineweaver-Burk plots for irreversible inhibition, and I can't quite figure it out. My best guess is that it would look like noncompetitive inhibition, where Vmax decreases due to the loss of available enzyme, while Km would be unchanged for the still-available enzymes. I guess it doesn't make sense to include non-available enzymes in determining Vmax, while not including them for Km, however.

@aldol16 ?

 

[aldol16]

Your intuition is correct. This is low yield, but irreversible inhibition generally involves covalent modification of the enzyme such that it's "taken out of service." As such, it will decrease the Vmax because you have less enzyme but will not affect Km because of the active enzymes present, there's no change in affinity for substrate.