Method for the quantitative determination of plasminogen activators

Claim 1

A method for the quantitative determination of plasminogen activators, inhibitors thereof and plasminogen preactivators, and trypsin, trypsin inhibitors and trypsinogen in human and other mammal body fluids and tissue extracts, which comprises: (1) reacting said body fluids or tissue extracts with a substrate which has the following structure: R.sup.1 --X--Y--Z--NH--R.sup.2 wherein X represents a group having the formula ##STR5## in which R 3 is a straight or branched alkyl radical having 1 to 7 carbon atoms or a cyclohexyl or cyclohexylmethyl radical, Y represents a seryl group or a glycyl group, Z represents an arginyl group, R 1 represents hydrogen or an acyl or sulfonyl group and R 2 represents an aromatic hydrocarbon radical optionally carrying substituents which permit chromophoric or fluorescent activity, -NH-R 2 being a chromophoric or fluorescent group, and which has the property to release a split product of formula NH 2 R 2 under the action of plasminogen activators, and (2) measuring by photometric, spectrophotometric or fluorescence-photometric methods the quantity of the split product NH 2 R 2 formed by the hydrolytic action of the biologically active factors on the substrate.

Claim 2

A method for the quantitative determination of plasminogen activators, inhibitors thereof and plasminogen preactivators, and trypsin, trypsin inhibitors and trypsinogen in human and other mammal body fluids and tissue extracts, which comprises: (1) reacting said body fluids or tissue extracts with a substrate which has the following structure: R.sup.1 --X--Y--Z--NH--R.sup.2 wherein X represents a group having the formula ##STR5## in which R 3 is a straight or branched alkyl radical having 1 to 7 carbon atoms or a cyclohexyl or cyclohexylmethyl radical, Y represents a seryl group or a glycyl group, Z represents an arginyl group, R 1 represents hydrogen or an acyl or sulfonyl group and R 2 represents an aromatic hydrocarbon radical optionally carrying substituents which permit chromophoric or fluorescent activity, -NH-R 2 being a chromophoric or fluorescent group, and which has the property to release a split product of formula NH 2 R 2 under the action of plasminogen activators, and (2) measuring by photometric, spectrophotometric or fluorescence-photometric methods the quantity of the split product NH 2 R 2 formed by the hydrolytic action of the biologically active factors on the substrate.

Claim 4

The method according to claims 1 or 2 which comprises using a buffer having a pH of 8.2 to 8.6 and an ionic strength of 0.15 to 1.0 and containing 0.02 to 0.2 trypsin-inhibitor units of aprotinin and/or 0.001 to 10 antithrombin units of hirudin per ml.