Abstract: Fluorogenic substrates for proteolytic enzymes having the formula: ##STR1## or acid salts thereof wherein: R.sub.1 is hydrogen-L, hydrogen-D, benzoyl, benzenesulfonyl, glutaryl, pyroglutamyl, carbobenzoxy, D-serine, or carbobenzoxy-serine;R.sub.2 is hydrogen, phenyl, a straight, branched or cyclic alkyl having 1 to 4 carbons, or propionic acid;R.sub.3 is hydrogen, straight or branched or cyclic alkyl having 1 to 4 carbons, 4-aminobutane, or 3-guanidylpropane;R.sub.4 is methyl, 4-aminobutane, or 3-guanidylpropane;R.sub.5 is a fluorogenic moiety, severable from said compound by a proteolytic enzyme and having different fluorescent property when severed from said compound than when forming part of said compound.The enzymes, when reacting with the substrate, remove the fluorogenic group R.sub.5 producing an increase in its fluorescence. The increase of the fluorescence is an indication of the activity of the enzyme present. Specific enzymes thusly detectable include plasmin, thrombin, the factors X.sub.a, XI.sub.

Abstract: Fluorogenic substrates for proteolytic enzymes having the formula: ##STR1## or acid salts thereof wherein: R.sub.1 is hydrogen-L, hydrogen-D, benzoyl, benzenesulfonyl, glutaryl, pyroglutamyl, carbobenzoxy, D-serine, or carbobenzoxy-serine;R.sub.2 is hydrogen, phenyl, a straight, branched or cyclic alkyl having 1 to 4 carbons, or propionic acid;R.sub.3 is hydrogen, straight or branched or cyclic alkyl having 1 to 4 carbons, 4-aminobutane, or 3-guanidylpropane;R.sub.4 is methyl, 4-aminobutane, or 3-guanidylpropane;R.sub.5 is a fluorogenic moiety, severable from said compound by a proteolytic enzyme and having different fluorescent property when severed from said compound than when forming part of said compound.The enzymes, when reacting with the substrate, remove the fluorogenic group R.sub.5 producing an increase in its fluorescence. The increase of the fluorescence is an indication of the activity of the enzyme present. Specific enzymes thusly detectable include plasmin, thrombin, the factors X.sub.a, XI.sub.

Abstract: Transferase and protease activity in homogenates and biological solutions is fluorometrically determined at wavelengths corresponding generally to those used for fluorometric NADH-linked determinations by utilizing novel substrate compositions consisting essentially of certain fluorogenic 5-aminoisophthalic acid derivatives coupled to amino acid constituents specific to the transferases and proteases under investigation.