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Dear Friends
I need clarification regarding the Km value in the
metabolism studies.
I am working on the metabolism studies of NCE's, we
determined the Km value for NCE by using the rat
liver microsomes. Can i use the same Km value
(obtained by using rat liver microsomes) for human,
monkey and Mouse metabolism studies.
Is Km value will be same or it will change with
different species?
Thanks in advance
Kind regards
G.Venkatesh
Research Student
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I would think Km might very easily vary from species to species, and
might
even vary between males and females within the same species and strain.
I definitely get different rates of metabolism for the compounds I
commonly
work with in human male vs. male rat liver microsomes.
Good luck!
-Rachel
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Dear Dr Vankatesh,
In my opinion, Km should change across species.
Km is an enzyme-related parameter (and, furthermore, in the case of
microsomes, it is likely an apparent Km of a combination of
biotransformation reactions involving more than one enzyme).
Since metabolic enzymes differ in nature and in amount according to
species, it might be risky to assume identity of Km value across
species.
Kind regards,
F. Massiere, PhD
ADME-PK Group Leader, Oroxcell
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The following message was posted to: PharmPK
Dear Venkatesh
As per your querry, the km value would defenitely change for different
species and also the gender with in the species.You cannot use the km
value
of one species with others.
Regards
Mohd.Khalid Pasha
Research Executive
Orchid Research Laboratories
R & D
Old Mahabalipuram Road
Sholinganallur
Chennai - 600 119
Phone: +91-44-24501474 (extn:229)
Fax : +91-44-24501396
+91-44-24501650
E-mail: mkhalidp.aaa.orchidpharma.com
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