I am facing problem to fit my ITC data manually in Origin or Prism and henceforth need the equation to do the same. I have went through the link given
http://www.isbg.fr/IMG/pdf/itc_data_analysis_in_origin.pdf
But it doesn't give a definitive sequential binding equation for 2 sites. I need a definitive equation for the same.
And I had been using GE healthcare ITC 200 microcal previously which comes up with Origin software but right now using Malvern ITC which uses its own software, is there any problem anybody is facing in the aforesaid machine??
You can analyze the data (*.itc) with Origin (ITC module in Origin 7).
Anyway, the Data Analysis Manual gives most of required information for data analysis.
In any case, what problems are you facing? Very often, when having problems at analyzing ITC data the reason lies either on the data (low quality, artifacts, unspecific signal contributions) or in the data analysis procedure (wrong model, wrong assumptions...).
Images illustrating the problems are always helpful for figuring out what could be happening.
Adrian Velazquez-Campoy , Hi, I didn't had problem previously while fitting my data in the Origin7 given along with ITC. But right now, I was trying to fit the curve in my computer but was unable to get the proper equation for Sequential fitting.
Further, while fitting in sequential fit in Malvern ITC software, I am not getting the binding constants I obtained using the previous version with Origin software.
Hence I need the proper equation for Sequential fit to fit my data.
Then:
- Does the new Malvern software not have the Sequential Binding model?
- Do Origin and Malvern software packages fit differently the same experiment?
Kaustav Gangopadhyay - the software for the MicroCal PEAQ-ITC from Malvern does use the same Sequential Binding model that is used for the Origin software for MicroCal iTC200 and VP-ITC. In the PDF of the link you provided, the equations for fitting are in the appendix.
Please note that for the sequential binding sites model with PEAQ-ITC software, the upper limit is 5 sites (for Origin the limit was higher). It is important to note that with this model, each binding site is assumed to have a N of 1 - if it is not 1, the fit will not be reliable
The PEAQ-ITC software uses a different algorithm for baseline integration, as well. You can manually adjust the integration baseline
During the fitting with PEAQ-ITC software, there are assigned upper and lower bounds for each parameter - are any of your fits hitting these limits? If do, change the appropriate upper/lower bound and re-fit (note that Origin for ITC also has limits fr the fitting parameters)
I know from my experience using both the PEAQ-ITC software and Origin for ITC is that I sometimes have to make initial guesses in the parameters when I fit the sequential and 2 sets of sites model.
How are you correcting for the heat of dilution/control experiments? PEAQ-ITC software has different options compared to Origin for ITC.
Have you taken the exact same data set and analye it using both the PEAQ-ITC software and Origin for ITC?
As Adrian Velazquez-Campoy said, actual data and images of the fits are helpful. Feel free to email me data files.
This may help?: https://www.cif.iastate.edu/sites/default/files/uploads/Other_Inst/ITC/Origin%20Lesson%2010.pdf
Verna Frasca , thanks for your suggestion. One expert from your company do came here and helped us to understand the entire software and now its good to go for us. Sorry to be late to reply and thanks to everyone for their valuable help.
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