The substrate compound 3 in which the one or more non proteinaceous fluorescent moiety comprises a dye selected from a xanthene dye, a rhodamine dye, a fluorescein dye, a cyanine dye, a phthalocyanine dye, {TAIL ~ a squaraine dye} and {HEAD ~ a bodipy dye} 
The substrate compound 3 in which the one or more non proteinaceous fluorescent moiety comprises a dye selected from a xanthene dye , a rhodamine dye , a fluorescein dye , a cyanine dye , a phthalocyanine dye , { TAIL ~ a squaraine dye } and { HEAD ~ a bodipy dye }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD