Metabolism USMLE Step 1 Practice Question
A 52 year old woman with metastatic renal cell carcinoma enrolls in a trial of a drug that irreversibly binds an allosteric site on a signaling enzyme and reduces its catalytic activity. In vitro testing shows that adding more substrate does not restore the maximal reaction rate. Which of the following best describes the kinetic effect of this drug?
Answer choices
- ADecreased Km with increased Vmax
- BDecreased Vmax with unchanged KmCorrect answer
- CIncreased Vmax with unchanged Km
- DDecreased Km only
- EIncreased Km only
- FIncreased Km with decreased Vmax (mixed inhibition)
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.