{HEAD ~ Further processing} of {TAIL ~ the mature form} apparently occurs in some instances to yield biologically active fragments of the protein 
{ HEAD ~ Further processing } of { TAIL ~ the mature form } apparently occurs in some instances to yield biologically active fragments of the protein
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH