Quantitative determination of the binding of epsilon-aminocaproic acid to native plasminogen.

Markus, Gabor; DePasquale, J L; Wissler, F.C.

doi:10.1016/s0021-9258(17)38163-2

Cited by 196 publications

(42 citation statements)

References 33 publications

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“…6-AHA inhibited the binding of plasminogen to the U937 and GM 1380 cells. This inhibition was observed in a concentration range consistent with occupancy of the high affinity lysine-binding site (15) which is associated with the first kringle of plasminogen (13). The failure of fibrinogen at 5 gM to inhibit plasminogen binding to the cells presumably reflects the low affinity of fibrinogen for the high affinity lysine-binding site of plasminogen (14).…”

Section: Discussionmentioning

confidence: 74%

“…50 % inhibition was obtained at 2.5 and 10 ~tM 6-AHA for the GM 1380 and U937 cells, respectively. As the Kd for the high affinity lysine-binding site of plasminogen is "~9 laM compared to 5 mM for the low affinity lysine-binding sites (15), the data suggest that the high affinity site must be unoccupied for interaction of plasminogen with the cells to occur. The binding The cells were treated with 500 ttg trypsin in 0.5 mM EDTA for 30 min at 37°C.…”

Section: Table I Specificity Of Urokinase and Plasminogen Binding To U93 7 And Gm1380 Cellsmentioning

confidence: 91%

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The plasminogen system and cell surfaces: evidence for plasminogen and urokinase receptors on the same cell type.

Plow

Freaney

Plescia

et al. 1986

The Journal of Cell Biology

450

265

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Abstract. The capacity of cells to interact with the plasminogen activator, urokinase, and the zymogen, plasminogen, was assessed using the promyeloid leukemic U937 cell line and the diploid fetal lung GM1380 fibroblast cell line. Urokinase bound to both cell lines in a time-dependent, specific, and saturable manner (Kd = 0.8-2.0 nM). An active catalytic site was not required for urokinase binding to the cells, and 55,000-mol-wt urokinase was selectively recognized. Plasminogen also bound to the two cell lines in a specific and saturable manner. This interaction occurred with a Kd of 0.8-0.9 IxM and was of very high capacity (1.6-3.1 x 107 molecules bound/cell). The interaction of plasminogen with both cell types was partially sensitive to trypsinization of the cells and required an unoccupied high affinity lysine-binding site in the ligand. When plasminogen was added to the GM1380 cells, a line with high intrinsic plasminogen activator activity, the bound ligand was comprised of both plasminogen and plasmin. Urokinase, in catalytically active or inactive form, enhanced plasminogen binding to the two cell lines by 1.4-3.3-fold. Plasmin was the predominant form of the bound ligand when active urokinase was added, and preformed plasmin can also bind directly to the cells. Plasmin on the cell surface was also protected from its primary inhibitor, a2-antiplasmin. These results indicate that the two cell lines possess specific binding sites for plasminogen and urokinase, and a family of widely distributed cellular receptors for these components may be considered. Endogenous or exogenous plasminogen activators can generate plasmin on cell surfaces, and such activation may provide a mechanism for arming cell surfaces with the broad proteolytic activity of this enzyme.XPRESSION of specific proteinase activities at cell surfaces is a phenotypic feature of a variety of cells and is a frequently elicited response of cells to stimulation and transformation (22,32,33,36). Plasminogen activators (PA) l are among the most broadly distributed of such cell surface proteinases (27,37,39,40). Urokinase (UK) is representative of one of the two major types of PA enzymes. This type of PA is expressed by a variety of cells including many tumor cells (3, 27, 37) and activated mononuclear cells (27,33,36). UK is highly specific for plasminogen and can activate the zymogen to plasmin by cleavage of a single peptide bond (26). Plasmin, in addition to its primary role in the proteolysis of fibrin, is a broad spectrum proteinase which may participate in such general functions as cell migration and differentiation, tissue remodeling, and inflammation (9,17,25). Control of UK synthesis and secretion and production of specific inhibitors of PA and plasmin are identified 1. Abbreviations used in this paper: 6-AHA, 6-aminohexanoic acid; DIPplasmin and DIP-UK, diisopropylphosphoryl-plasmin and -urokinase obtained by treating plasmin or UK with 5 mM diisopropyl fluorophosphate; PA, plasminogen activator; UK, urokinase. mechanisms for regulation of...

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Section: Discussionmentioning

confidence: 74%

Section: Table I Specificity Of Urokinase and Plasminogen Binding To U93 7 And Gm1380 Cellsmentioning

confidence: 91%

The plasminogen system and cell surfaces: evidence for plasminogen and urokinase receptors on the same cell type.

Plow

Freaney

Plescia

et al. 1986

The Journal of Cell Biology

450

265

View full text Add to dashboard Cite

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“…Structures of lysine and its synthetic analogues 2 – 5 . EACA ( 2 ) and TXA ( 3b ) bind to the K1 domain with K D values of 9 μM and 1.1 μM, respectively.…”

Section: Ligands Of the Lysine Binding Sitementioning

confidence: 99%

Fibrinolysis Inhibitors: Potential Drugs for the Treatment and Prevention of Bleeding

et al. 2019

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Hyperfibrinolytic situations can lead to lifethreatening bleeding, especially during cardiac surgery. The approved antifibrinolytic agents such as tranexamic acid, εaminocaproic acid, 4-aminomethylbenzoic acid, and aprotinin were developed in the 1960s without the structural insight of their respective targets. Crystal structures of the main antifibrinolytic targets, the lysine binding sites on plasminogen's kringle domains, and plasmin's serine protease domain greatly contributed to the structure-based drug design of novel inhibitor classes. Two series of ligands targeting the lysine binding sites have been recently described, which are more potent than the most-widely used antifibrinolytic agent, tranexamic acid. Furthermore, four types of promising active site inhibitors of plasmin have been developed: tranexamic acid conjugates targeting the S1 pocket and primed sites, substrate-analogue linear homopiperidylalanine-containing 4amidinobenzylamide derivatives, macrocyclic inhibitors addressing nonprimed binding regions, and bicyclic 14-mer SFTI-1 analogues blocking both, primed and nonprimed binding sites of plasmin. Furthermore, several allosteric plasmin inhibitors based on heparin mimetics have been developed.

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“…EACA is a synthetic lysine analog that competitively inhibits Glu-plg accumulation in the thrombus by its affinity and blockage of LBS. [31] There was significantly less Glu-plg accumulation when EACA was administered before laser injury compared to PTCI and control. These results show that Glu-plg accumulation in microthrombi is LBS-dependent.…”

Section: Discussionmentioning

confidence: 88%

Pre-administration of a carboxypeptidase inhibitor enhances tPA-induced thrombolysis in mouse microthrombi: Evidence from intravital imaging analysis

Mathews

Honkura

Sano

et al. 2022

Thrombosis Research

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Introduction: Thrombolysis using recombinant tissue-type plasminogen activator (rt-PA) is the pharmacological treatment of choice in acute thrombotic events. However, a narrow therapeutic window and bleeding complications limit its use. We describe the role of carboxypeptidase inhibitor from potato tuber (PTCI), an inhibitor of activated thrombin-activatable fibrinolysis inhibitor (TAFIa), on Glu-plasminogen accumulation and microthrombus dynamics in vivo and demonstrate its influence on rt-PA-mediated thrombolysis. Materials and methods: In conjunction with real-time intravital two-photon excitation fluorescence microscopy, we produced and imaged laser-induced microthrombi in the mesenteric venules of Green Fluorescent Protein (GFP)-expressing mice. We examined microthrombus dynamics and thrombolysis patterns in vivo by measuring the changes in the fluorescence intensity of labeled Glu-plasminogen following administration of epsilon aminocaproic acid (EACA), PTCI, and rt-PA. Results: PTCI enhanced Glu-plasminogen accumulation at the core of the thrombus by inhibiting TAFIa, while EACA inhibited this process. Exogenous rt-PA effectively triggered Glu-plasminogen activation within the thrombus and promoted thrombolysis. Administration of PTCI and rt-PA together showed no significant benefit on thrombolysis compared to rt-PA administration alone. However, early-phase systemic administration of PTCI before thrombolytic therapy by rt-PA expedited clot lysis as evidenced by significantly faster time to reach peak Glu-plasminogen fluorescence intensity and shorter time to achieve near-complete clot lysis (P = 0.014 and P = 0.003, respectively). Conclusions: PTCI potentiates rt-PA-mediated thrombolysis when administered early in acute thrombotic events. Further studies are warranted to explore the potential of TAFI inhibitors as adjunct agents in thrombolysis or thromboprophylaxis.

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Quantitative determination of the binding of epsilon-aminocaproic acid to native plasminogen.

Cited by 196 publications

References 33 publications

The plasminogen system and cell surfaces: evidence for plasminogen and urokinase receptors on the same cell type.

The plasminogen system and cell surfaces: evidence for plasminogen and urokinase receptors on the same cell type.

Fibrinolysis Inhibitors: Potential Drugs for the Treatment and Prevention of Bleeding

Pre-administration of a carboxypeptidase inhibitor enhances tPA-induced thrombolysis in mouse microthrombi: Evidence from intravital imaging analysis

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