When {TAIL ~ the pH} rises above the pI of the protein, {HEAD ~ the protein} assumes a net negative charge 
When { TAIL ~ the pH } rises above the pI of the protein , { HEAD ~ the protein } assumes a net negative charge
OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH