Detection of {TAIL ~ an increase} in fluorescent signal indicates {HEAD ~ the presence} of the enzyme in the sample 
Detection of { TAIL ~ an increase } in fluorescent signal indicates { HEAD ~ the presence } of the enzyme in the sample
OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH