Measuring protein isoelectric points by AFM - based force spectroscopy using trace amounts of sample by Shifeng Gu, Xiaoying Zhu, Dominik Jańczewski, Serina Siew Chen Lee, Tao He, Serena Lay Ming Teo, & G. Julius Vancso. (frogheart.ca)
As long as they are not denatured by heat, they are not precipitated at their isoelectric points. (dairyprocessinghandbook.com)
Next, they added this substance to a chemical soup called EDDAC, raising its isoelectric point. (sciencemag.org)