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Topic: Can michaelis menton equation determine IC50  (Read 482 times)

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Offline distheho

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Can michaelis menton equation determine IC50
« on: January 22, 2021, 04:31:24 PM »
If I plot the % reduced (from uninhibited reaction) enzyme reaction rate vs inhibitor concentration, is the "Km" the IC50 for that specific enzyme concentration?

Offline Babcock_Hall

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Re: Can michaelis menton equation determine IC50
« Reply #1 on: January 23, 2021, 08:48:11 AM »
I am a little puzzled by your reference to the enzyme concentration.  Can you explain?

Offline distheho

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Re: Can michaelis menton equation determine IC50
« Reply #2 on: January 23, 2021, 10:53:48 AM »
It is my understanding that IC50 is based on enzyme concentration.

Offline Babcock_Hall

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Re: Can michaelis menton equation determine IC50
« Reply #3 on: January 23, 2021, 11:55:27 AM »
https://pubmed.ncbi.nlm.nih.gov/4202581/
There is a 1973 paper by Cheng and Prusoff that discusses the meanings of IC50.  With respect to the Michaelis-Menten equation, KM does not depend on enzyme concentration.  Just glancing at the paper, IC50 values do depend on substrate concentration.

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