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Prep4USMLE Forum » USMLE Step 1 Forum » Physiology Forum

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4 Posts

kris2c
Forum Senior

Topics: 30
Posts: 108

02/19/04 - 07:59 AM

3.- All of the following are true concerning competitive inhibitors except:

a) They are structurally similar to their substrate
b) They binds to a similar location on the enzyme as the substrate
c) They can be overcome by high concentrations of the intended substrate
d) They do not affect Vmax
e) Km decreases in comparison to the uninhibited enzyme.

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Kris2c

auubar
Forum Senior

Topics: 30
Posts: 182

02/19/04 - 11:16 AM

I think it is E but I am not sure.

dxtxpx
Forum Guru

Topics: 259
Posts: 1,233

02/19/04 - 11:30 AM

Yes auubar is right as Competitive Inhibitor competes directly against substrate for the same binding site, increase in KM, VMAX unchanged

kris2c
Forum Senior

Topics: 30
Posts: 108

02/19/04 - 02:03 PM

3) Answer: e
Km ↑, which means that the enzyme affinity ↓ for the substrate because there are competitive inhibitors in the environment. Vmax decreases as result of noncompetitive inhibitors.

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Kris2c

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