March 29, 2024, 10:12:27 AM
Forum Rules: Read This Before Posting


Topic: Can michaelis menton equation determine IC50  (Read 1711 times)

0 Members and 1 Guest are viewing this topic.

Offline distheho

  • Very New Member
  • *
  • Posts: 2
  • Mole Snacks: +0/-0
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

  • Chemist
  • Sr. Member
  • *
  • Posts: 5592
  • Mole Snacks: +319/-22
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

  • Very New Member
  • *
  • Posts: 2
  • Mole Snacks: +0/-0
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

  • Chemist
  • Sr. Member
  • *
  • Posts: 5592
  • Mole Snacks: +319/-22
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.

Sponsored Links