SC is {HEAD ~ a conjugated substance} that is said {TAIL ~ first member} of a specific binding pair 
is
SC is { HEAD ~ a conjugated substance } that is said { TAIL ~ first member } of a specific binding pair
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH