| 摘要 |
Human cytomegalovirus (HCMV) protease is a slow-processing enzyme in vitro. Disclosed herein are improved fluorogenic and radiometric peptide substrates for CMV protease. The improved substrates have a Tbg-Tbg-Asn(NMe2) sequence replacing the Val-Val-Asn sequence, corresponding to the P4-P2 residues of the maturation site of the enzyme. The incorporation of this new sequence in a variety of substrates has afforded substrates with improved kinetic parameters compared to homologues containing the natural sequence only. For example, the substrate 2-aminobenzoyl-Tbg-Tbg-Asn(NMe2)-AlaiSer-Ser-Arg-Leu-Tyr(3-NO2)ARG-OH displayed a kcat/Km value of 15940 M--1-s-1, i.e. over 60-fold greater than that of the equivalent, non-optimized substrate in identical conditions. The new substrates find use in assays which can evaluate and characterize HCMV protease inhibitors having low nanomolar potency.
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