Mixed inhibitors

[limitless12]

Why is it that in noncompetitive inhibition, Km remains the same, but in Mixed inhibition, with inhibition of the E complex, Km increases(lowers affinity for substrate). both of them binds allosterically, so why is it that one has an increase in Km while the other remains the same

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[MaxPlancker]

1) Please post questions like this in the MCAT forum.
2) Think about the definition of Km…and then think about non/mixed effects on Vmax…and you should be able to come up with the answer.

 

[tantacles]

Moving to MCAT

 

[deleted647690]

Why is it that in noncompetitive inhibition, Km remains the same, but in Mixed inhibition, with inhibition of the E complex, Km increases(lowers affinity for substrate). both of them binds allosterically, so why is it that one has an increase in Km while the other remains the same

In my Kaplan book, it says that noncompetitive inhibitors bind to both the enzyme and enzyme substrate complex equally, while mixed inhibitors bind to them unequally. That is the only difference between the two. I'm pretty sure there is no other way to tell the difference. The Km for noncompetitive stays the same because there are still active enzymes that are not bound by the inhibitor, so the affinity does not change.

 

[χmaverickχ]

From my biochem course I'm currently taking...