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