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