Chromogenic compounds and their use as enzyme substrates

Claim 1

A compound of the formula W--P--B--X--NH--R wherein W is R 1 CO-- wherein R 1 is C 1 -C 6 aliphatic hydrocarbon, C 6 -C 10 aromatic hydrocarbon, C 7 -C 10 araliphatic hydrocarbon; or C 6 -C 10 alkaryl, or W is R 2 OCO-- wherein R 2 is C 1 -C 6 aliphatic hydrocarbon, C 7 -C 10 araliphatic hydrocarbon, or alkyl 1-6 sulfonylalkyl 2-6 , or W is benzenesulfonyl or C 7 -C 10 alkarylsulfonyl; P is valine, serine, Phe-Pro, Val-Glu-Gly, Val-Leu, Gly-Pro-Glu-Gly, or Ile-Glu-Gly, side chain groups of which may be substituted by protective groups; B is arginine, lysine, phenylalanine, tyrosine, or homoarginine; X is an L-amino acid selected from the group consisting of phenylalanine, tyrosine, valine, leucine, serine, glycine, and Leu-Phe, side chain groups of which may be substituted by protective groups; and R is an aromatic hydrocarbon, which may be substituted; wherein X--NH--R is a chromogenic group which is cleaved by hydrolytic enzymatic action to form a compound H 2 N--R, the amount of which can be measured by photometric, spectrophotometric, or fluorescence-photometric methods.