An initial attempt of protection by {HEAD ~ acylation} of sulfhydryl group resulted in maintaining duration of the activity to {TAIL ~ some extent} 
An initial attempt of protection by { HEAD ~ acylation } of sulfhydryl group resulted in maintaining duration of the activity to { TAIL ~ some extent }
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL