Abstract: Peptide sequences consisting of 2-4 amino acids with high affinity and comparatively high specificity to a number of various, physiologically important proteases are known to have been synthetized before. Such sequences with an added C-terminal marker have been widely used as substrates for the quantitative determination of the kind of proteases mentioned above. The method is based on the fact that the marker is split off under influence of the enzyme and that the liberated marker possesses an easily measurable, for instance, optic property which differs from that of the original substrate. The type of markers used until today have mainly been chromophores or fluorophores which can be quantified by photometry or fluorometry.The present invention relates to a new type of markers coupled to known peptide sequences. These markers are luminol or isoluminol which in their free state can be brought to luminate intensely, but lose considerably in luminescence when they are amide-bound to a peptide sequence.

Abstract: Easily split enzyme substrates for the quantification of proteases having the general formulaR.sub.1 --p-Glu--A.sub.1 --A.sub.2 --NH--R.sub.2,whereR.sub.1 =H or a protective group, preferably t-butyloxycarbonyl, benzyloxycarbonyl;A.sub.1 =Gly, Ala, Val, Leu, Ile, Ser, Thr, Pro, Pip, Phe or Tyr;A.sub.2 =Arg or Lys;R.sub.2 =an aromatic, possibly substituted, hydrocarbon group, wherein --NH--R.sub.2 is a physico-chemically determinable group, preferably a chromogenic or fluorogenic group which is split by a present enzyme and then forms a cleavage product of the formula H.sub.2 N--R.sub.2 the amount of which can be quantified.Processes for the production of said substrates. Method in the laboratory diagnostics of proteases using said substrates.

Abstract: Easily split enzyme substrates for the quantification of proteases having the general formulaR.sub.1 --p-Glu--A.sub.1 --A.sub.2 --NH--R.sub.2,whereR.sub.1 =H or a protective group, preferably t-butyloxycarbonyl, benzyloxycarbonyl;A.sub.1 =Gly, Ala, Val, Leu, Ile, Ser, Thr, Pro, Pip, Phe or Tyr;A.sub.2 =Arg or Lys;R.sub.2 =an aromatic, possibly substituted, hydrocarbon group, wherein --NH--R.sub.2 is a physico-chemically determinable group, preferably a chromogenic or fluorogenic group which is split by a present enzyme and then forms a cleavage product of the formula H.sub.2 N--R.sub.2 the amount of which can be quantified.Processes for the production of said substrates. Method in the laboratory diagnostics of proteases using said substrates.

Abstract: Serine proteases in a substance such as blood are determined by contacting the substance with a novel chromogenic or fluorgenic substrate for serine proteinases and spectrophotometrically measuring the quantity of a chromophore or fluorescent compound released from the substrate by serine proteases in the substance. The novel substrate has the amino acid sequence-ILe-A-Gly-Arg-wherein A is Asp or Glu substituted in the carboxylic group by esterification or amidation. The novel substrate increases sensitivity and accuracy of the determination.

Abstract: Tripeptide derivatives of the formulaH-D-X-Phe-Arg-Yin whichX is selected from the group consisting of Pro and PheY is selected from the group consisting of O--R.sub.1 and NH--R.sub.2 in whichR.sub.1 is selected from the group consisting of straight, branched and cyclic alkyl group with 1-12 C atoms, andR.sub.2 is selected from the group consisting of H, straight, branched and cyclic alkyl group with 1-12 C atoms, and physiologically acceptable salts thereof.A process for producing said tripeptide derivatives by synthesis and purification methods which are known in the peptide chemistry.Pharmaceutical preparations comprising said tripeptide derivatives.

Abstract: Chromogenic or fluorogenic enzyme substrates for serine proteases containing the amino acid sequence Ile-A-Gly-Arg wherein A is Asp or Glu substituted in the carboxylic group by esterification or amidation, a method of preparation thereof, and use thereof.