1.The thrombogram: monitoring thrombin generation in platelet-rich plasma.
Hemker HC1, Giesen PL, Ramjee M, Wagenvoord R, Béguin S. Thromb Haemost. 2000 Apr;83(4):589-91.
A method is described in which thrombin activity in clotting plasma can be monitored through the continuous measurement of the fluorescent split-product of the substrate Z-Gly-Gly-Arg-AMC. The signal is not impaired by turbidity; therefore proper measurement is not disturbed by the occurrence of a clot or the presence of platelets and direct measurement in platelet rich plasma is possible.
2.Antiplasmin-cleaving enzyme is a soluble form of fibroblast activation protein.
Lee KN1, Jackson KW, Christiansen VJ, Lee CS, Chun JG, McKee PA. Blood. 2006 Feb 15;107(4):1397-404. Epub 2005 Oct 13.
Circulating antiplasmin-cleaving enzyme (APCE) has a role in fibrinolysis and appears structurally similar to fibroblast activation protein (FAP), a cell-surface proteinase that promotes invasiveness of certain epithelial cancers. To explore this potential relationship, we performed comparative structure/function analyses of the 2 enzymes. APCE from human plasma and recombinant FAP (rFAP) exhibited identical pH optima of 7.5, extinction coefficients (in(280 nm)(1%)) of 20.2 and 20.5, common sequences of tryptic peptides, and cross-reactivity with FAP antibody. APCE and rFAP are homodimers with monomeric subunits of 97 and 93 kDa. Only homodimers appear to have enzymatic activity, with essentially identical kinetics toward Met-alpha2-antiplasmin (Met-alpha2AP) and peptide substrates. APCE and rFAP cleave both Pro3-Leu4 and Pro12-Asn13 bonds of Met-alpha2AP, but relative kcat/Km values for Pro12-Asn13 are about 16-fold higher than for Pro3-Leu4.
3.Antiplatelet agents can promote two-peaked thrombin generation in platelet rich plasma: mechanism and possible applications.
Tarandovskiy ID1, Artemenko EO, Panteleev MA, Sinauridze EI, Ataullakhanov FI. PLoS One. 2013;8(2):e55688. doi: 10.1371/journal.pone.0055688. Epub 2013 Feb 6.
BACKGROUND: Thrombin generation assay is a convenient and widely used method for analysis of the blood coagulation system status. Thrombin generation curve (TGC) is usually bell-shaped with a single peak, but there are exceptions. In particular, TGC in platelet-rich plasma (PRP) can sometimes have two peaks.
4.Purification and characterization of a new 120 kDa alkaline proteinase of Trypanosoma cruzi.
Santana JM1, Grellier P, Rodier MH, Schrevel J, Teixeira A. Biochem Biophys Res Commun. 1992 Sep 30;187(3):1466-73.
A new alkaline proteinase activity was identified in cell-free extracts of Trypanosoma cruzi epimastigotes on the basis of its ability to hydrolyze the fluorogenic substrate N-Z-Gly-Gly-Arg-AMC. The optimal activity was at pH 8.0. After a three step-chromatography procedure using two anionic columns (DEAE-Sepharose and Mono Q) and a chromatofocusing column (Mono P), the proteolytic activity was associated with a single 120 kDa protein and was called Tc 120 proteinase. The molecular mass of the proteinase was confirmed by direct visualization of the proteolytic activity using a fluorometric assay on SDS-PAGE. The Tc 120 proteinase which also cleaves N-Z-Arg-AMC, N-Z-Phe-Arg-AMC and N-glutaryl-Gly-Arg-AMC substrates, is a cysteine-type proteinase with an unusual low sensitivity to E-64.