[Protein-analysis] Re: MicroCAL Origin 7.0 Software for ITC

Dr Engelbert Buxbaum via proteins%40net.bio.net (by engelbert_buxbaum At hotmail.com)
Sun Jan 21 12:57:16 EST 2007

Tyler Collins wrote:

> I am attempting to use our ITC MCS Unit from MicroCal to quantify the
> homodimer dissociation of a dimeric protein to monomer.  Unfortunately,
> homodimeric species are difficult to analyze using the old Origin software.
> In addition, MicroCal will not provide a free upgrade in software to
> accommodate the models you want to use.  Instead, they are charging $2500
> for software that includes a dimer dissociation model that would be useful
> to my work.  Does anyone know where to get a possible bootleg version of the
> software, or do you have suggestions, books, articles that may aid in
> helping me write my own macro?

You can use any curve-fitting software you like, but you have to define
a suitable mathematical model for the fit. Curve fitting is for example
covered in 

        AUTHOR= {W.H. Press and B.P. Flannery and S.A. Teukolsky and
W.T. Vetterling},
        TITLE= {Numerical recipes in {P}ascal: The art of scientific
        YEAR= {1989},
        PUBLISHER= {Cambridge University Press},
        ADDRESS= {Cambridge},
        LANGUAGE= {engl}

or similar books on numerical mathematics. A good implementation of the
Simplex-algorithm can be found in 

   AUTHOR=  {M.S. Caceci and W.P. Cacheris},
   TITLE=   {Fitting Curves to Data},
   JOURNAL= {Byte},
   YEAR=    {1984},
   Issue=   {5},
   PAGES=   {340-362},

The advantage of Simplex over Marquard-Levenberg is that you can also
fit data to a system of differential (rate-) equations, using numerical
integration (Runge-Kutta-algorithm):

        AUTHOR= {G. Heinzel},
        TITLE= {Beliebig genau: {M}oderne {R}unge-{K}utta {V}erfahren
zur {L}ösung von {D}ifferentialgleichungen},
        YEAR= {1992},
        JOURNAL= {c't},
        PAGES= {172-185},
        VOLUME= {8},
        NUMBER= {8},
        MONTH= {Aug},
        LANGUAGE= {dt}

Hence it is not necessary to analytically integrate the system first,
which can be challenging. 

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