The Effect Of Plasmin On Factor XIII (Fibrin Stabilizing Factor)

1981 ◽  
Author(s):  
D M Rider ◽  
J M McDonagh

The action of plasmin on several blood clotting factors has been studied; however, controversy exists concerning the effect of plasmin on factor XIII. Factor XIII was purified from plasma and platelets and then exposed to plasmin for up to 6 hours. Plasmin to factor XIII ratios ranged from 0.03-0.1 casein units plasmin per mg factor XIII. These plasmin levels exhibited strong proteolytic activities against B-casein and purified human fibrinogen Following incubation of factor XIII (activated and unactivated) with plasmin the mixtures were electrophoresed on 7% SDS-polyacrylamide gels. The factor XIII preparations were assayed for 14C-putrescine incorporating activity before and after exposure to plasmin. Platelet factor XIII was,labeled With 125Iodine and lableled a subunit (activated and unactivated) was exposed to plalmin for up to 2 hours. These mixtures were electrophoresed on 12.5% Urea-SDS Polyacrylamide gels and a radioactivity profile was determined for each gel.Following extensive exposure to Plasmin the relative molecular weights of the factor XIII subunits (a, a* and b)remained constant and almost all (90-100%) of the 14C-put-rescine incorporating activity was recovered. The radio-activity profiles of the gels of 125I-labeled platelet factor XIII were identical before and after incubation with plasmin. Plasmin did not activate factor XIII in the assay system nor did factor XIII inactivate plasmin by crosslinking it. These experiments indicate that plasmin does not activate or degrade factor XIII and that the b subunit of plasma factor XIII plays no role in protecting the a subunit from the action of plasmin.

1993 ◽  
Vol 69 (03) ◽  
pp. 282-285 ◽  
Author(s):  
László Muszbek ◽  
János Polgár ◽  
Zoltán Boda

SummaryThe potentially active A subunit of factor XIII of blood coagulation has also been detected in platelets and monocytes/macrophages though the exact function of this cellular protransglutaminase has not yet been elucidated. In physiological conditions the first step in the activation of plasma factor XIII is the removal of an activation peptide from the N-terminal end of subunit A by thrombin. The A subunit then, in the presence of Ca2+, dissociates from the inhibitory B subunit and assumes an active conformation. Cellular factor XIII, which lacks B subunit, can be proteolytically activated in vitro by thrombin and the intracellular Ca2+ sensitive protease, calpain, in the same way as plasma factor XIII subunit A, and calpain has been suggested as the intracellular protease involved in the activation of cellular factor XIII in platelets. In the present experiments it was shown by SDS PAGE that during long-term stimulation of platelets with thrombin nondisulfide-crosslinked high M r protein polymers not penetrating the concentrating gel were formed. The lack of these polymers in thrombin-stimulated factor XIII deficient platelets clearly indicated that their formation in normal platelets was due to factor XIII that became active during platelet activation. However, no release of the activation peptide could be detected by Western blotting during this process. Similarly, no proteolytic cleavage of factor XIII was detectable when platelets were stimulated by Ca2+ ionophore through this stimulus activated calpain as it was clearly demonstrated by the breakdown of major intracellular calpain substrates. The results indicate: 1) during thrombin induced platelet activation factor XIII becomes active and crosslinks platelet protein, 2) platelet factor XIII is not an intracellular substrate of calpain, 3) cellular factor XIII could be activated without the proteolytic removal of activation peptide. It is presumed that the nonproteolytic pathway for the activation of cellular factor XIII, we reported most recently, might have physiological implications under such conditions.


1975 ◽  
Author(s):  
Jan McDonagh ◽  
Richard P. McDonagh

A new method for studying the interactions of plasma factor XIII subunits, as well as purifying both plasma and platelet factor XIII, has been developed using an organomer-curial linked to agarose. Native plasma factor XIII a subunit binds to the ligand accompanied by b subunit, which can be dissociated from the ligated a subunit by treatment with thrombin and calcium. With various combinations of thrombin, calcium, and alteration of ionic strength it has been shown that: (a) both unactivated a subunit and thrombin activated a’ subunit bind to the ligand; (b) “excess” b subunit present in highly purified preparations of plasma factor XIII dissociates and can be eluted at low ionic strength in the absence of calcium or thrombin; (c) in our preparations of highly purified plasma factor XIII approximately 40% of b subunit is in “excess”; (d) the remaining b subunit can be eluted with thrombin and calcium; (e) both a and a’ subunits can be eluted with dithiothreitol ; (f ) when plasma factor XIII zymogen is applied to the column approximately equal amounts of a and b subunits co-elute with dithiothreitol. These observations offer further evidence for the roles of thrombin and calcium in the activation of plasma factor XIII and provide a new tool for studying the structure-function relationships of factor XIII.Supported by Grants HL 14228 and HL 06350 from the National Institutes of Health, U.S.A.


1976 ◽  
Vol 36 (03) ◽  
pp. 542-550 ◽  
Author(s):  
Mircea P. Cucuianu ◽  
K Miloszewski ◽  
D Porutiu ◽  
M. S Losowsky

SummaryPlasma factor XIII activity measured by a quantitative assay was found to be significantly higher in hypertriglyceridaemic patients (type IV and combined hyperlipoproteinaemia), as compared to normolipaemic controls. No such elevation in plasma factor XIII activity was found in patients with type IIa hyperlipaemia. Plasma pseudocholinesterase was found to parallel the elevated factor XIII activity in hypertriglyceridaemic subjects.In contrast, platelet factor XIII activity was not raised in hyperlipaemic subjects, and plasma factor XIII was found to be normal in a normolipaemic subject with throm-bocythaemia.It was concluded that there is no significant contribution from platelets to plasma factor XIII activity, and that the observed increase in plasma factor XII in hypertriglyceridaemia results from enhanced hepatic synthesis of the enzyme.


Blood ◽  
2000 ◽  
Vol 96 (7) ◽  
pp. 2479-2486 ◽  
Author(s):  
István Balogh ◽  
Gabriella Szôke ◽  
Levente Kárpáti ◽  
Ulla Wartiovaara ◽  
Éva Katona ◽  
...  

Abstract Val34Leu polymorphism of the A subunit of coagulation factor XIII (FXIII-A) is located in the activation peptide (AP) just 3 amino acids away from the thrombin cleavage site. This mutation has been associated with a protective effect against occlusive arterial diseases and venous thrombosis; however, its biochemical consequences have not been explored. In the current study it was demonstrated that the intracellular stability and the plasma concentration of FXIII of different Val34Leu genotypes are identical, which suggests that there is no difference in the rate of synthesis and externalization of wild-type and mutant FXIII-A. In contrast, the release of AP by thrombin from the Leu34 allele proceeded significantly faster than from its wild-type Val34 counterpart. By molecular modeling larger interaction energy was calculated between the Leu34 variant and the respective domains of thrombin than between the Val34 variant and thrombin. In agreement with these findings, the activation of mutant plasma FXIII by thrombin was faster and required less thrombin than that of the wild-type variant. Full thrombin activation of purified plasma FXIII of different genotypes, however, resulted in identical specific transglutaminase activities. Similarly, the mean specific FXIII activity in the plasma was the same in the groups with wild-type, heterozygous, and homozygous variants. Faster activation of the Leu34 allele hardly could be associated with its presumed protective effect against venous thrombosis. No such protective effect was observed in a large group of patients with familial thrombophilia.


Blood ◽  
1985 ◽  
Vol 66 (5) ◽  
pp. 1028-1034 ◽  
Author(s):  
CS Greenberg ◽  
JV Dobson ◽  
CC Miraglia

Abstract The binding of plasma factor XIII to fibrinogen or fibrin that has been chemically or enzymatically induced to polymerize was studied. Factor XIII binding was assayed using a 3H-putrescine incorporation assay and an 125I-plasma factor XIII binding assay. More than 80% of the native and radiolabeled plasma factor XIII was bound to fibrin I formed by reptilase in EDTA, citrate, or heparin anticoagulated plasma. Plasma factor XIII and 125I-factor XIII was bound (89.6% to 92.5%) to fibrin II formed by thrombin in either citrate or EDTA anticoagulated plasma. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of 125I-plasma factor XIII bound to fibrin I or fibrin II formed by reptilase or thrombin in the presence of EDTA demonstrated the b2- subunit remained bound to the a-chains or thrombin-cleaved a-chains. In the presence of calcium chloride and thrombin, the b2-subunit dissociated and factor XIIIa was bound. Protamine sulfate caused fibrinogen polymerization in the absence of divalent cations and reduced both plasma factor XIII and immunologic fibrinogen levels. Fibrinogen polymerized by protamine sulfate bound plasma factor XIII and the a2-subunit of 125I-platelet factor XIII. Plasma factor XIII was also bound to sonicated non-cross-linked fibrin II in either normal plasma or afibrinogenemic plasma. Plasma levels of several coagulation proteins were unchanged after the addition of reptilase, protamine sulfate, or sonicated fibrin to plasma. These results demonstrate that a specific binding site for the a2-subunit of plasma factor XIII is present on polymerized fibrinogen, fibrin I, and fibrin II. Furthermore, the presence of divalent cations, thrombin-cleavage of plasma factor XIII, and release of fibrinopeptides A or B are not required for plasma factor XIII binding to polymerized fibrinogen and fibrin.


1988 ◽  
Vol 59 (03) ◽  
pp. 372-377 ◽  
Author(s):  
Garry W Lynch ◽  
Sharron L Pfueller

SummaryPlatelets contain factor XIII, an A subunit zymogen form of transglutaminase (TGase), that is activated by thrombin. In addition a thrombin-independent TGase (A#) was observed. A# was formed in platelet preparations lysed at acid pH, and its generation inhibited by protease inhibitors and alkaline pH. When maximal A# activity was generated in acidified lysates no further TGase activity could be induced by subsequent treatment with thrombin. Both FXIII zymogen and A# copurified as for F XIII, from either alkaline or from acidified platelet lysates respectively, by the conventional procedure. The pH optima, Km’s for NN dimethyl casein, molecular weights, heat lability of active forms, requirements for calcium and reducing agents, and immunological characteristics of both TGases were the same. Studies with inhibitor substrates suggested that a thrombin-like cathepsin C or carboxypeptidase was responsible for A# formation. Purified F XIII zymogen could be activated directly by cathepsin C. Thus, the predominant, and probably only, TGase of platelets is factor XIII, which may be activated either by thrombin or by endogenous platelet acid protease(s).


1993 ◽  
Vol 69 (04) ◽  
pp. 397-400 ◽  
Author(s):  
Daniela Lukacova ◽  
Guy L Reed

SummaryTo facilitate the analysis of the catalytic subunit of factor XIII we have developed a method for the immunoaffinity purification of this protein from platelets. This method employs a monoclonal antibody that binds to the a-subunit of factor XIII. The anti-factor XIII antibody was immobilized on agarose and then incubated with platelet lysate. Subsequently factor XIII was isolated from the platelet lysate in a single step with a 41% yield as measured by enzyme assay. The purified platelet factor XIII appeared nearly homogeneous when analyzed by polyacrylamide electrophoresis and by immunoblotting with another factor XIII monoclonal antibody.


1975 ◽  
Author(s):  
D. Bannerjee ◽  
M. W. Mosesson

Human plasma Factor XIII (F. XIII) complex is composed of two types of noncovalently linked polypeptide chains termed a and b; only the a chain possesses catalytic potential. Platelet Factor XIII is comprised solely of a chains which are identical to those found in plasma. In this study platelets were utilized as a source of unbound a chains to characterize F. XIII (a chain)-binding activity in plasma and its subfractions. Upon exclusion chromatography of unheated plasma or of an unheated ammonium sulfate (20% sat.) subfraction, F. XIII activity emerged in a peak corresponding to a mol. wt. of < 500,000 (region 1). If these samples had first been heated at 60° to precipitate fibrinogen, F. XIII was eluted in a peak corresponding to a mol wt. of about 300,000 (region 2). Chromatography of the platelet zymogen alone resulted in a F. XIII peak corresponding in position to that of monomeric a chain (mol. wt. 80,000, region 3).Exclusion chromatography of the unheated ammonium sulfate fraction yielded, in addition to the F. XIII peak in region 1, a protein peak (peak II) in region 2 which contained no F. XIII. When peak II was mixed with platelet F. XIII, and again subjected to exclusion chromatography, the platelet F. XIII peak shifted from its expected position in region 3 and emerged instead in region 2 ; this behavior demonstrated F. XIII (a chain)-binding activity within peak II. The same chromatographic shift was observed in mixtures of platelet F. XIII and normal plasma or that from a patient with congenital F. XIII (a chain) deficiency. Immunochemical analyses of chromatographic fractions indicated that a chain-binding was due to complexing of a chains with freely circulating b chains. Since a chains and b chains have different biosynthetic sites we conclude that b chains serve as an extracellular F. XIII (a chain)-binding protein.Supported by NHLI grant HL-11409.


1979 ◽  
Author(s):  
U. Helgstrand ◽  
H-E Jensen ◽  
H.O. Kruse-BIinkenberg ◽  
J. Gormsen

The fibrinolytic activity was investigated histiochemically in patients with ulcer disease before and after Cimetidine and parietal cell vagotomy. The method is based on the fibrin slide method described by Todd 1958. Biopsies were taken during gastroscopy before and after treatment as follows: 3 biopsies from patients with duodenal ulcer (I from greater curvature in the corpus, II from the antrum, and III close to the ulcer in the duodenum). The control material were patients with uncharacteristic dyspepsia. The fibrinolytic activity was demonstrated by covering clean microslides with a fibnn-ogensolution (human fibrinogen, grade L, AB Kabi, contaminated with plasminogen and factor XIII) clotted by thrombin. The slides were kept in moist chamber, the frozen tissue cut in 8 a sections was mounted on the film. All analyses were made double with 3-8 sections on each slide. Fixation in formalin was made 0, 10, 20, and 30 minutes after incubation in moist chamber 137°C.), and the slides stained. In the microscope the activity was graded 1 for small punctate areas of lysis, 2 for large confluent areas, and 3 for massive fibrin digestion. Results show grade 2 or 3 for biopsies taken close to the ulcer before treatment,none or grade 1 in the others. After treatment the activity close to the ulcer is reduced to none or grade 1. So far, 150 biopsies have been analysed.


2000 ◽  
Vol 84 (10) ◽  
pp. 524-527 ◽  
Author(s):  
L. Muszbek

SummaryBlood coagulation factor XIII (FXIII), for its unique features, used to be considered a stepchild among clotting factors. In contrast to other proenzyme clotting factors, it is the precursor of a transglutaminase and not of a proteolytic enzyme. By cross-linking peptide-bound glutamine and lysine side chains transglutaminases make, rather than break, peptide bonds. Activated FXIII (FXIIIa) cross-links fibrin α-chains and γ-chains and covalently attaches α2-plasmin inhibitor to fibrin α-chains to strengthen fibrin mechanically and to protect it from fibrinolysis. In addition to being a clotting factor, FXIII is also an intracellular proenzyme present in platelets and monocytes/macrophages. The plasma factor is of heterotetrameric structure consisting of two potentially active A (FXIII-A) and two inhibitory/protective B (FXIII-B) subunits (A2B2), while its cellular counterpart is a dimer of FXIII-A. Plasma FXIII is activated by the concerted action of thrombin and Ca2+. Thrombin cleaves FXIII-A at Arg37-Gly38, then in the presence of Ca2+ FXIII-B dissociates and FXIII-A assumes an active configuration (reviewed in ref. 1).


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