A protein assumes a neutral charge when the pH of the environment is equivalent to {HEAD ~ pI} of {TAIL ~ the protein} 
of
A protein assumes a neutral charge when the pH of the environment is equivalent to { HEAD ~ pI } of { TAIL ~ the protein }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL