Why are proteins least souble at their isoelectric point/pI?

Question

Yeah as above.

Answer 1

Normally proteins carry a net charge which depends on the nature of the amino acid side chains. Charged molecules tend to have a greater affinity for the surrounding water molecules, rather than for each other, and so stay in solution. At the pI the molecules have no net charge and no longer repel each other, allowing them to aggregate and precipitate