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Michael Hannigan
Michael Hannigan, Internet Researcher
Category: General
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Experience:  Extensive experience in research and problem solving.
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Who was the first person to define or use the term IC50

Customer Question

Who was the first person to define or use the term IC50 (concentration of inhibitor required to cut enzyme activity in half)?
Submitted: 1 year ago.
Category: General
Customer: replied 1 year ago.
The first instance I can find is Heymann & Fieser in 1948 but it is clear that it was already commonly in use by then.
Expert:  Michael Hannigan replied 1 year ago.

I believe it would be Hans Andersag, in 1934

He was at Bayer I.G. Farbenindustrie A.G. laboratories in Eberfeld, Germany, when he developed an anti-malerial agent, which wasn't released until 1946.

Mike

Customer: replied 1 year ago.
Hello Michael,
Do you have a reference? I spent a couple of hours this morning looking at Andersag papers from the 30s without success. But at $30 a pop, I do not really want to keep looking at random.
Thanks for teh help.
Joe
Customer: replied 1 year ago.
Michael,
I can't really give a satisfaction reply until the question is answered. I have read a number of Andersag papers but not found teh correct reference. Since they cost between $20 and $50 to download, I am not too happy downloading lots of papers only to see synthetic information on chloroquine and its analogs. I went as far as to contact Bayer in Germany to see if they had any information about IC50s and Andersag but I have not heard back from them. If it is Andersag and I can identify the exact source, you will end up with an Excellent. If it is not Andersag, then there is no service.
Maybe the source you used to find Andersag actually has a more complete citation for teh work.
Joe
Customer: replied 1 year ago.
Right now, I would have to say that it is not possible to rate the service since it has not been completed. If someone put a gun to my head, I would have to say the service is bad because I get an email everyday asking me to rate the service despite my continued requests for verified information as opposed to a belief.