Unfortunately, {TAIL ~ discrepancies} among recent reports have added to the general uncertainty as to {HEAD ~ the true enzymatic function} for this family of proteins 
Unfortunately , { TAIL ~ discrepancies } among recent reports have added to the general uncertainty as to { HEAD ~ the true enzymatic function } for this family of proteins
OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH