A general method for the preparation of internally quenched fluorogenic protease substrates using solid-phase peptide synthesis.

A general scheme for obtaining a fluorescent donor/acceptor peptide substrate via solid-phase synthesis methodology is presented. The key feature of this method is the design of a glutamic acid derivative that has been modified on the carboxyl side chain with a 5-[(2'-aminoethyl)-amino]naphthelenesulfonic acid (EDANS) to create a fluorescent donor moiety that can be incorporated near the C-terminus of the peptide substrate. The corresponding fluorescent acceptor group containing a 4-[[4-(dimethylamino)phenyl]azo]benzoic acid (DABCYL) can then be attached to the resin-bound peptide at the N-terminus while all side-chain groups are still fully protected. Substrates for renin and HIV proteinase are synthesized as examples.