Dear Sam Mahdi ,

According to:

https://web.expasy.org/protparam/protparam-doc.html

The ProtParam tool parameters such as the molecular weight and theoretical pI are calculated as in Compute pI/Mw:

https://web.expasy.org/compute_pi/pi_tool-doc.html

According to the info they state that: Protein pI is calculated using pK values of amino acids described in Bjellqvist et al.

References are:

Bjellqvist, B.,Hughes, G.J., Pasquali, Ch., Paquet, N., Ravier, F., Sanchez, J.-Ch., Frutiger, S. & Hochstrasser, D.F. The focusing positions of polypeptides in immobilized pH gradients can be predicted from their amino acid sequences. Electrophoresis 1993, 14, 1023-1031.

Bjellqvist, B., Basse, B., Olsen, E. and Celis, J.E. Reference points for comparisons of two-dimensional maps of proteins from different human cell types defined in a pH scale where isoelectric points correlate with polypeptide compositions. Electrophoresis 1994, 15, 529-539.

Gasteiger E., Hoogland C., Gattiker A., Duvaud S., Wilkins M.R., Appel R.D., Bairoch A.; Protein Identification and Analysis Tools on the ExPASy Server; (In) John M. Walker (ed): The Proteomics Protocols Handbook, Humana Press (2005). Full text - Copyright Humana Press.

This might be the info you are looking for.

Best regards.

Thanks Rob Keller , I ended up finding their values by looking at their github. They had them all laid out (they were using a different equation than I was to calculate pI, the values were more or less the same).