Assay of procarboxypeptidase U, a novel determinant of the fibrinolytic cascade, in human plasma
KA Schatteman, FJ Goossens, SS Scharpé… - Clinical …, 1999 - academic.oup.com
KA Schatteman, FJ Goossens, SS Scharpé, HM Neels, DF Hendriks
Clinical chemistry, 1999•academic.oup.comAbstract Background: Procarboxypeptidase U (proCPU) is a novel proenzyme found in
human plasma. The active form, carboxypeptidase U (CPU; EC 3.4. 17.20), retards the rate
of fibrinolysis through its ability to cleave C-terminal lysine residues on fibrin partially
degraded by plasmin. This reduces the number of high-affinity plasminogen-binding sites on
fibrin. Methods: We developed an assay to determine the proCPU concentration in human
plasma. The assay involved quantitative conversion of proCPU to active CPU by thrombin …
human plasma. The active form, carboxypeptidase U (CPU; EC 3.4. 17.20), retards the rate
of fibrinolysis through its ability to cleave C-terminal lysine residues on fibrin partially
degraded by plasmin. This reduces the number of high-affinity plasminogen-binding sites on
fibrin. Methods: We developed an assay to determine the proCPU concentration in human
plasma. The assay involved quantitative conversion of proCPU to active CPU by thrombin …
Abstract
Background: Procarboxypeptidase U (proCPU) is a novel proenzyme found in human plasma. The active form, carboxypeptidase U (CPU; EC 3.4.17.20), retards the rate of fibrinolysis through its ability to cleave C-terminal lysine residues on fibrin partially degraded by plasmin. This reduces the number of high-affinity plasminogen-binding sites on fibrin.
Methods: We developed an assay to determine the proCPU concentration in human plasma. The assay involved quantitative conversion of proCPU to active CPU by thrombin-thrombomodulin, a very efficient activator of proCPU, followed by determination of the enzymatic activity of CPU with the substrate hippuryl-l-arginine, using an HPLC-assisted determination of the released hippuric acid. Using this method, we established a reference interval based on 490 healthy individuals.
Results: The mean proCPU concentration, determined after activation of the zymogen in diluted plasma and expressed as CPU activity, was 964 U/L, with a SD of 155 U/L. The population showed a gaussian distribution. However, we noticed important differences related to age and the use of hormone preparations.
Conclusions: The sensitivity and precision of the method make it suitable for routine clinical determinations and as a reference procedure.
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