In article <48qtcj$2jb at sun0.urz.uni-heidelberg.de>, Thomas W Bluem
<tbluem at ix.urz.uni-heidelberg.de> wrote:
> Help ... Help ... Help ... Help ...
>> What does this mean:
>> K = 1 mM ???
>> What is K ?
>> Thanks in advance.
>>> T. W. Bluem, Dept. of Anatomy and Cellbiology, University of Heidelberg,
The definition of this, can be found in most textbooks of pharmacology
(under Hill equation),
but in brief it relates to the dissociation constant of an Agent, A to its
It is often refered to as the [A]50, which simply relates to the
concentration at which there
is a 50% effect. This latter is most appropriatly used in indirect
measurements, whereas Kd is
measured in more direct ways, such as by radioligand binding experiments.
For a quick reference, see; Jenkinson, D.H. et al, Pharmacological Reviews
In your case, Kd=1 mM, means that at a concentration of 1 mM, half your
receptors will be occupied
(A fairly high Kd value in terms of affinity)
anders.fugelli at basalmed.uio.no
Institute of Neurophysiology
University of Oslo