Analysis of scatchard plots: seeking for approriate software

Andrew J. Doherty doherty at bsa.bristol.ac.uk
Wed Sep 18 02:44:34 EST 1996


Helmut, Kipp wrote:
> 
> Dear colleges,
> 
> I am dealing with a substrate (D-glucose) interacting with two receptors.
> From the tissue preparation under investigation I know that there are two
> receptors present, a high and a low affinity system. I would like to
> approximate the Km's of these two receptors. Satchard plots show
> a hyperbolic curve, thus matching the two systems by eye and do a graphical
> evaluation turned out to be very unreliable.
> 
> My question to the community is: Are there reliable computer programms for
> the analysis of these scatchard plots available to solve my problem?
> Experiance on this topic, suggestions for commercial software or pointers
> to software available on the net are highly appreciated. Please reply to
> this group or to my e-mail (helmut.kipp at mpi-dortmund.mpg.de).
> 
> Thank you for considering my problem
> 
> ------
> Helmut Kipp, Ph. D.
> Max-Planck-Institut fuer molekulare Physiologie
> Postfach 102664, 44026 Dortmund, Germany
> Phone: +49-231-1206-484, Fax: +49-231-1206-464
> E-mail: helmut.kipp at mpi-dortmund.mpg.de
Yes, there's plenty of software out there to analyse this sort of data.
I've used EBDA, Enzfitter and also InPlot (from GraphPad). EBDA is a
purely Scatchard analysis package while InPlot and Enzfitter are general
curve fitting programs, which will fit data to any equation you write.
Both EBDA and InPlot do f-test analysis to determine if 1 or 2-site
models give the best fit to the data. EBDA was excellent in terms of the
analysis, but horrible to use (this was a few years ago now, so there
may be more user-friendly versions around now), while InPlot had it's
limitations, but was very simple to use. "You pay your money and take
your choice" as they say. Also, many of the figure drawing packages,
like SigmaPlot (PC) or Kaleidograph (Mac) have non-linear curve fitting
protocols, for which you can write your own equations, but in my humble
opinion, they're not as good as a dedicated data analysis package. You
should be able to get most of these from most scientific software
houses.

Hope this helps 
-- 
***********************************************
   Dr Andrew Doherty                          
   Department of Anatomy                   
   School of Medical Sciences             
   University Walk                               
   Bristol                                            
   UK
   BS8 1TD

   e-mail  Doherty at bsa.bristol.ac.uk

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