Inhibition Curves: one more trouble

[Dmitry Yuryev]

   Note my paper which proves that upgrades of traditional
Cheng-Prusoff procedure (ncluding computer approaches) can not
be used for analysis of inhibition experiment beyond "Cheng-Prusoff
conditions".
   The summary is appended below. Full text (MS Word 6.0 f.W. format)
is available from: 
ftp://garbo.uwasa.fi/pc/science/crsaf_02.zip

-----------------------


   REFINING CHENG-PRUSOFF EQUATION

   Dmitriy K. Yuryev   
   yur77 at glas.apc.org
   http://www.glasnet.ru/~yur77

   A generalisation of the Cheng-Prusoff formula relating affinity
constant and the concentration of inhibitor giving 50% inhibition has
been derived for the case when concentrations of ligands are not in
a great excess. It shows that methods ensuring precise solving of
binding equations (including computer approaches and equations derived
in the present work) can not be used if these "Cheng-Prusoff
conditions" of ligands' excess are not observed. 
   The trouble is that beyond these conditions analysis becomes 
unreliable: the error contained in estimations of necessary parameters
appears abruptly multiplied in the calculated affinity constant