Here are the following numbers I have calculated;
We were given a substrate to plot againist velocity and 3 enzymes to plot as well. From the data:
Enzyme A Ki= 2.575 | Kcat = 50 | Km= 3.33
Enzyme B Ki = 10.33 | Kcat = 16.65 | Km = 33.3
Enzyme C Ki= 1.00 | Kcat = 10 | Km = .2
I'm having trouble understanding which is the best inhibitor because:
A has the highest Kcat- best collision efficiency
C has the lowest Km - the highest affinity for its substrate
C has the lowest Ki- which means it binds the tightest.
The answer depends on what you want from your inhibitor as there is no clear best chemically.
Km is the substrate concentration required for the enzyme to work at half its maximum rate. Purely competitive inhibition will increase Km but will not alter kcat (and hence the maximum rate). ...
The solution offers guidance and things to consider to pick the best inhibitor out of three when given their respective Kcat, Km and Ki values.