The term does not imply that {HEAD ~ the sequence} is {TAIL ~ the only amino acid chain present}, but that it is essentially free of material naturally associated with it 
is
The term does not imply that { HEAD ~ the sequence } is { TAIL ~ the only amino acid chain present } , but that it is essentially free of material naturally associated with it
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH