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