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