Preferably, the reactive group is hydrogen are {HEAD ~ the reactive site} is {TAIL ~ a hydroxy group} 
is
Preferably , the reactive group is hydrogen are { HEAD ~ the reactive site } is { TAIL ~ a hydroxy group }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL