scholarly journals Properties of sulfatides in factor-XII-dependent contact activation

Blood ◽  
1982 ◽  
Vol 59 (1) ◽  
pp. 69-75 ◽  
Author(s):  
G Tans ◽  
JH Griffin
Keyword(s):  
Normal Values ◽  
Limited Proteolysis ◽  
Factor Xii ◽  
Contact Activation ◽  
Amidolytic Activity ◽  
Prolonged Incubation ◽  
Coagulant Activity ◽  
Plasma Factor ◽  
Normal Human ◽  
Kallikrein Activity

Abstract Incubation of normal human plasma with low amounts of sulfatides resulted in the initiation of intrinsic coagulation and the appearance of kallikrein activity. The optimal initiation of procoagulant and kallikrein amidolytic activity was dependent on the presence of factor XII, high molecular weight kininogen, and prekallikrein. Since the activated partial thromboplastin clotting times in prekallikrein- deficient plasma approach normal values upon prolonged incubation with kaolin, this phenomenon of autocorrection was studied and found to be even more pronounced in the presence of sulfatides. Autocorrection was essentially completed in 5 min in the presence of sulfatides, whereas a preincubation of 15–20 min was required in the presence of kaolin. The limited proteolysis of 125I-factor XII in plasma during incubation with activating material or during clotting was determined. Cleavage of factor XII was more rapid and more extensive in the presence of sulfatides than in the presence of kaolin. In prekallikrein-deficient plasma, factor XII cleavage was completed within 5 min in the presence of sulfatides and within 15 min in the presence of kaolin. Thus, the appearance of factor-XII-dependent coagulant activity correlates with the limited proteolysis of factor XII when normal or prekallikrein- deficient plasma is activated by sulfatides or kaolin.

scholarly journals Properties of sulfatides in factor-XII-dependent contact activation

Blood ◽  
1982 ◽  
Vol 59 (1) ◽  
pp. 69-75 ◽  
Author(s):  
G Tans ◽  
JH Griffin
Keyword(s):  
Normal Values ◽  
Limited Proteolysis ◽  
Factor Xii ◽  
Contact Activation ◽  
Amidolytic Activity ◽  
Prolonged Incubation ◽  
Coagulant Activity ◽  
Plasma Factor ◽  
Normal Human ◽  
Kallikrein Activity

Incubation of normal human plasma with low amounts of sulfatides resulted in the initiation of intrinsic coagulation and the appearance of kallikrein activity. The optimal initiation of procoagulant and kallikrein amidolytic activity was dependent on the presence of factor XII, high molecular weight kininogen, and prekallikrein. Since the activated partial thromboplastin clotting times in prekallikrein- deficient plasma approach normal values upon prolonged incubation with kaolin, this phenomenon of autocorrection was studied and found to be even more pronounced in the presence of sulfatides. Autocorrection was essentially completed in 5 min in the presence of sulfatides, whereas a preincubation of 15–20 min was required in the presence of kaolin. The limited proteolysis of 125I-factor XII in plasma during incubation with activating material or during clotting was determined. Cleavage of factor XII was more rapid and more extensive in the presence of sulfatides than in the presence of kaolin. In prekallikrein-deficient plasma, factor XII cleavage was completed within 5 min in the presence of sulfatides and within 15 min in the presence of kaolin. Thus, the appearance of factor-XII-dependent coagulant activity correlates with the limited proteolysis of factor XII when normal or prekallikrein- deficient plasma is activated by sulfatides or kaolin.

scholarly journals The contact activation mechanism in human plasma: activation induced by dextran sulfate

Blood ◽  
1982 ◽  
Vol 59 (6) ◽  
pp. 1225-1233 ◽  
Author(s):  
F van der Graaf ◽  
FJ Keus ◽  
RA Vlooswijk ◽  
BN Bouma
Keyword(s):  
Human Plasma ◽  
Dextran Sulfate ◽  
Activation Mechanism ◽  
Factor Xii ◽  
Contact Activation ◽  
Prolonged Incubation ◽  
Normal Plasma ◽  
Essential Components ◽  
Factor Xiia ◽  
Kallikrein Activity

Abstract Incubation of normal human plasma with dextran sulfate for 7 min at 4 degrees C generates kallikrein amidolytic activity. No kallikrein activity is generated in factor XII or prekallikrein-deficient plasma and only small amounts (8%) in high molecular weight (HMW) kininogen- deficient plasma. Addition of specific antisera directed against prekallikrein or HMW kininogen to normal plasma blocked the generation of kallikrein activity by dextran sulfate. Thus, factor XII, prekallikrein, and HMW kininogen are essential components for optimal activation of prekallikrein. The role of limited proteolysis in the activation of prekallikrein induced by dextran sulfate was studied by adding 125I-prekallikrein to plasma. The generation of kallikrein activity paralleled the proteolytic cleavage of prekallikrein as judged on SDS gels in the presence of reducing agents. The same cleavage fragments were observed as obtained by activation of purified prekallikrein by beta-factor-XIIa. Addition of 131I-HMW kininogen and 125I-factor XII or 131I-HMW kininogen and 125I-prekallikrein to normal plasma followed by activation with dextran sulfate and analysis on SDS gels indicated that the observed cleavage of prekallikrein and HMW kininogen is fast compared to the observed cleavage of factor XII, which is much slower and less extensive. During the first minutes of incubation of normal plasma with dextran sulfate, mainly alpha-factor- XIIa is formed. During prolonged incubation, beta-factor-XIIa is also formed.

Dextran Sulfate Induced Activation Of Prekallikrein In Normal Plasma And Inactivation Of Kallikrein

1981 ◽  
Author(s):  
F V D Graaf ◽  
J F A Keus ◽  
A Rietveld ◽  
R A A Vlooswijk ◽  
B N Bouma
Keyword(s):  
Dextran Sulfate ◽  
Limited Proteolysis ◽  
Maximum Activity ◽  
Factor Xii ◽  
C1 Inhibitor ◽  
Amidolytic Activity ◽  
Original Activity ◽  
Activity Maximum ◽  
Normal Plasma ◽  
Kallikrein Activity

Addition of dextran sulfate (DXS; Mr 500.000) to normal human plasma (n.h.p.) at 4° C results in the generation of kallikrein amidolytic activity. Maximum kallikrein activity is generated after 7 minutes in n.h.p., while no kallikrein activity is generated in Factor XII and Prekallikrein (PK) deficient plasma and only small amounts (8%) in High Mr Kininogen (HMWK) deficient plasma. Anti Factor XII, anti PK or anti HMWK added to n.h.p. blocked the formation of kallikrein activity. This shows that Factor XII, PK and HMWK are necessary for optimal activation of PK.By adding 125I-PK to n.h.p. followed by activation with DXS it was shown that the appearance of kallikrein activity is paralled by limited proteolysis of 125I-PK, as judged on reduced SDS gels. The same cleavage fragments were observed as obtained by activation of purified PK by ²-Factor XIIa (28.000 Mr form). Addition of 131I-HMWK and 125I-PK or 131I-HMWK rand I-Factor XII to normal plasma followed by activation with DXS indicated on SDS gels a similar rate of cleavage for HMWK and PK whereas Factor XII was cleaved less extensive.Inactivation of kallikrein in plasma was studied at 37°C after activation with DXS at 4°C. Kallikrein was rapidly inactivated, reaching a plateau after 4 minutes of 10% of its maximum activity. In Cj inhibitor deficient plasma kallikrein was less rapid inactivated and a plateau of 30% was reached after 9 minutes. 125I-PK was added to n.h.p. prior to activation at 4°C and inactivation at 37°C. This plasma was analyzed by crossed immunoelectrophoresis. Radioactivity was detected in the precipitin peak using anti C1 inhibitor and anti α2-macroglobulin (β2M) but not with anti antithrombin III. Using purified proteins it was shown that C1 inhibitor inhibited kallikrein amidolytic activity completely, whereas α2M inhibited this activity only to 25% of its original activity. This remaining amidolytic activity is that of the α2M-kallikrein complex. Complexes of kallikrein and inhibitor and kallikrein and α2M were observed on SDS gels in the presence and absence of reducing agents.

scholarly journals The contact activation mechanism in human plasma: activation induced by dextran sulfate

Blood ◽  
1982 ◽  
Vol 59 (6) ◽  
pp. 1225-1233 ◽  
Author(s):  
F van der Graaf ◽  
FJ Keus ◽  
RA Vlooswijk ◽  
BN Bouma
Keyword(s):  
Human Plasma ◽  
Dextran Sulfate ◽  
Activation Mechanism ◽  
Factor Xii ◽  
Contact Activation ◽  
Prolonged Incubation ◽  
Normal Plasma ◽  
Essential Components ◽  
Factor Xiia ◽  
Kallikrein Activity

Incubation of normal human plasma with dextran sulfate for 7 min at 4 degrees C generates kallikrein amidolytic activity. No kallikrein activity is generated in factor XII or prekallikrein-deficient plasma and only small amounts (8%) in high molecular weight (HMW) kininogen- deficient plasma. Addition of specific antisera directed against prekallikrein or HMW kininogen to normal plasma blocked the generation of kallikrein activity by dextran sulfate. Thus, factor XII, prekallikrein, and HMW kininogen are essential components for optimal activation of prekallikrein. The role of limited proteolysis in the activation of prekallikrein induced by dextran sulfate was studied by adding 125I-prekallikrein to plasma. The generation of kallikrein activity paralleled the proteolytic cleavage of prekallikrein as judged on SDS gels in the presence of reducing agents. The same cleavage fragments were observed as obtained by activation of purified prekallikrein by beta-factor-XIIa. Addition of 131I-HMW kininogen and 125I-factor XII or 131I-HMW kininogen and 125I-prekallikrein to normal plasma followed by activation with dextran sulfate and analysis on SDS gels indicated that the observed cleavage of prekallikrein and HMW kininogen is fast compared to the observed cleavage of factor XII, which is much slower and less extensive. During the first minutes of incubation of normal plasma with dextran sulfate, mainly alpha-factor- XIIa is formed. During prolonged incubation, beta-factor-XIIa is also formed.

Plasma Contact Activation and Decrease of Factor V Activity on Negatively-Charged Polyelectrolytes

1984 ◽  
Vol 51 (01) ◽  
pp. 061-064 ◽  
Author(s):  
M C Boffa ◽  
B Dreyer ◽  
C Pusineri
Keyword(s):  
Time Dependent ◽  
Initial Contact ◽  
Factor Xii ◽  
Factor V ◽  
Contact Activation ◽  
Polyelectrolyte Complexes ◽  
Plasma Factor ◽  
Fresh Plasma ◽  
Direct Adsorption

SummaryThe effect of negatively-charged polymers, used in some artificial devices, on plasma clotting and kinin systems was studied in vitro using polyelectrolyte complexes.Contact activation was observed as an immediate, transient and surface-dependent phenomenon. After incubation of the plasma with the polymer a small decrease of factor XII activity was noticed, which corresponded to a greater reduction of prekallikrein activity and to a marked kinin release. No significant decrease of factor XII, prekallikrein, HMW kininogen could be detected immunologically. Only the initial contact of the plasma with the polyelectrolyte lead to activation, subsequently the surface became inert.Beside contact activation, factor V activity also decreased in the plasma. The decrease was surface and time-dependent. It was independent of contact factor activation, and appeared to be related to the sulfonated groups of the polymer. If purified factor V was used instead of plasma factor V, inactivation was immediate and not time-dependent suggesting a direct adsorption on the surface. A second incubation of the plasma-contacted polymer with fresh plasma resulted in a further loss of Factor V activity.

scholarly journals A monoclonal anti-human plasma prekallikrein antibody that inhibits activation of prekallikrein by factor XIIa on a surface

Blood ◽  
1987 ◽  
Vol 70 (4) ◽  
pp. 1053-1062
Author(s):  
D Veloso ◽  
LD Silver ◽  
S Hahn ◽  
RW Colman
Keyword(s):  
Heavy Chain ◽  
Sodium Dodecyl ◽  
Factor Xii ◽  
Contact Activation ◽  
Fab Fragments ◽  
Microtiter Plates ◽  
Normal Plasma ◽  
Reducing Conditions ◽  
Factor Xiia ◽  
Kallikrein Activity

Of five IgGI/k murine monoclonal anti-human prekallikrein antibodies produced (MAbs), MAb 13G11 was selected for studying interaction of prekallikrein with factor XII and high-mol-wt kininogen (HMWK) during activation on a surface. Immunoblots from sodium dodecyl sulfate (SDS) gels showed that this MAb recognizes two variants (88 kd and 85 kd) of prekallikrein and kallikrein both in purified proteins and normal plasma. Under reducing conditions, kallikrein exhibits the epitope on the heavy chain but not on the light chains. Preincubation of MAb 13G11 with prekallikrein (added to prekallikrein-deficient plasma) or with normal plasma inhibited surface activation of prekallikrein 60% to 80%, as judged by amidolytic and coagulant assays. In normal plasma, inhibition by the Fab fragments was 87% of that with the entire MAb. Inhibition was not by competition between the MAb and HMWK, since neither binding of 13G11 to prekallikrein (coated on microtiter plates) was inhibited by an excess of HMWK, nor was hydrolysis of HMWK by kallikrein inhibited by 13G11. Using purified proteins in a system mimicking contact activation, inhibition by 13G11 of prekallikrein activation by factor XIIa, HMWK, and kaolin present was approximately 80%. Decreased inhibition (55% to 25%) occurred without HMWK or when kallikrein was used instead of prekallikrein. Kallikrein activity was not inhibited by 13G11 Fab fragments. These results indicate that the effect of 13G11 in plasma was neither dissociation of prekallikrein- HMWK complex nor a direct effect on kallikrein activity. Similar to the results in plasma, activation of prekallikrein, HMWK present, by factor XIIa bound to kaolin, was inhibited approximately 70% by 13G11. The results suggest a previously unrecognized site on the prekallikrein (heavy chain) required for its interaction with factor XIIa, either shared with the 13G11 epitope or located in very close proximity. The inhibition of kallikrein by intact 13G11 indicates that its binding site on the heavy chain is sterically related to the active site (light chain).

scholarly journals A monoclonal anti-human plasma prekallikrein antibody that inhibits activation of prekallikrein by factor XIIa on a surface

Blood ◽  
1987 ◽  
Vol 70 (4) ◽  
pp. 1053-1062 ◽  
Author(s):  
D Veloso ◽  
LD Silver ◽  
S Hahn ◽  
RW Colman
Keyword(s):  
Heavy Chain ◽  
Sodium Dodecyl ◽  
Factor Xii ◽  
Contact Activation ◽  
Fab Fragments ◽  
Microtiter Plates ◽  
Normal Plasma ◽  
Reducing Conditions ◽  
Factor Xiia ◽  
Kallikrein Activity

Abstract Of five IgGI/k murine monoclonal anti-human prekallikrein antibodies produced (MAbs), MAb 13G11 was selected for studying interaction of prekallikrein with factor XII and high-mol-wt kininogen (HMWK) during activation on a surface. Immunoblots from sodium dodecyl sulfate (SDS) gels showed that this MAb recognizes two variants (88 kd and 85 kd) of prekallikrein and kallikrein both in purified proteins and normal plasma. Under reducing conditions, kallikrein exhibits the epitope on the heavy chain but not on the light chains. Preincubation of MAb 13G11 with prekallikrein (added to prekallikrein-deficient plasma) or with normal plasma inhibited surface activation of prekallikrein 60% to 80%, as judged by amidolytic and coagulant assays. In normal plasma, inhibition by the Fab fragments was 87% of that with the entire MAb. Inhibition was not by competition between the MAb and HMWK, since neither binding of 13G11 to prekallikrein (coated on microtiter plates) was inhibited by an excess of HMWK, nor was hydrolysis of HMWK by kallikrein inhibited by 13G11. Using purified proteins in a system mimicking contact activation, inhibition by 13G11 of prekallikrein activation by factor XIIa, HMWK, and kaolin present was approximately 80%. Decreased inhibition (55% to 25%) occurred without HMWK or when kallikrein was used instead of prekallikrein. Kallikrein activity was not inhibited by 13G11 Fab fragments. These results indicate that the effect of 13G11 in plasma was neither dissociation of prekallikrein- HMWK complex nor a direct effect on kallikrein activity. Similar to the results in plasma, activation of prekallikrein, HMWK present, by factor XIIa bound to kaolin, was inhibited approximately 70% by 13G11. The results suggest a previously unrecognized site on the prekallikrein (heavy chain) required for its interaction with factor XIIa, either shared with the 13G11 epitope or located in very close proximity. The inhibition of kallikrein by intact 13G11 indicates that its binding site on the heavy chain is sterically related to the active site (light chain).

scholarly journals Enzymatic activities of activated and zymogen forms of human Hageman factor (factor XII)

Blood ◽  
1982 ◽  
Vol 60 (1) ◽  
pp. 64-70 ◽  
Author(s):  
M Silverberg ◽  
AP Kaplan
Keyword(s):  
Limited Proteolysis ◽  
Order Rate Constant ◽  
Procoagulant Activity ◽  
Factor Xii ◽  
Amidolytic Activity ◽  
Diisopropyl Fluorophosphate ◽  
Hageman Factor ◽  
First Order ◽  
Proteolytic Activities ◽  
Kinetics Of

Abstract Pro-Phe-Arg chloromethylketone (PPACMK) at 5.26 microM inactivated the amidolytic activity of native human Hageman factor with an apparent first-order rate constant of 0.75 min-1. The activated forms of Hageman factor, Hfa and HFf, were also inactivated by PPACMK with rate constants 0.82 and 0.72 min-1. These numbers indicate that the activity detectable in native Hageman factor is due to contamination with activated species. Uncleaved Hageman factor reacts slowly with 40 mM diisopropyl fluorophosphate with concomitant loss of its procoagulant activity. Incubation of native Hageman factor with PPACMK does not destroy its procoagulant activity, even in the presence of the activator dextran sulphate, but PPACMK inhibits autoactivation of Hageman factor, suggesting that no active site is formed in uncleaved, surface-bound Hageman factor. The activation of prekallikrein by Hageman factor under initial-rate conditions occurs after a lag and is prevented by an inhibitor of Hageman factor from corn. The kinetics of prekallikrein activation and the effects of inhibitors provide evidence that the amidolytic and proteolytic activities of human Hageman factor reside in the activated forms derived by limited proteolysis of the native molecule.

Changes in Plasma Prekallikrein, High and Low Molecular Weight Kininogens in Disseminated Intravascular Coagulation

1979 ◽  
Author(s):  
M. Yokouchi ◽  
K. Kosaka ◽  
T. Seki ◽  
M. Ogawara ◽  
R. Miura ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Disseminated Intravascular Coagulation ◽  
Marked Decrease ◽  
Normal Values ◽  
Low Molecular Weight ◽  
Factor Xii ◽  
Kinin System ◽  
Intravascular Coagulation ◽  
Plasma Factor ◽  
Kallikrein Kinin System

Changea in components in kallikrein-kinin system have been studied in 15 cases with disseminated Intravascular coagulation (DIC). Nine out of the total cases had infection and six cases had malignancy as primary diseases. Plasma prekallikrein (FKK) was determined by a radiochemical assay using 3H-TAME according to Imanari et al.(1974). High and low molecular weight kininogens (HMWK and LMWK) were bioassayed according to Uchida and Katori (in press). If plasma factor XII, measured in each case, was less than 50 % of normal, values of PKK and HMWK in examined plasma were caliculated from those in 1:1 mixture of examined plasma and normal plasma. All of PKK, HMWK and LMWK Showed moderate to marked decrease in every case with DIC. The values for PKK, HMWK and LMWK were 0.23 0.07 TAME unit/ml (normally 0.620.13), 0,20 0.07 ug(bradykinin equiv.)/ml (normally 0.66 0.14) and 1.24 0.44 ug/ml (normally 2.57 0.41), respectively. There was a significant correlation between PKK and antithrombin III levels (r=0.66, P 0.001) in those cases with DIC. PKK was also directly correlated with HMWK and factor XII. Decrease in PKK and HMWK may be chiefly due to consumption. The mechanism for reduction In LMWK, however, remains to be determined. It may be concluded that plasma prekallikrein, high and low molecular weight kininogens decrease in DIC.

The Fibronectin Type II Domain of Factor XII Ensures Zymogen Quiescence

2020 ◽  
Vol 120 (03) ◽  
pp. 400-411 ◽  
Author(s):  
Chantal C. Clark ◽  
Zonne L. M. Hofman ◽  
Wariya Sanrattana ◽  
Lyanne den Braven ◽  
Steven de Maat ◽  
...  
Keyword(s):  
Full Length ◽  
Activation Loop ◽  
Factor Xii ◽  
Type Ii ◽  
Contact Activation ◽  
Zymogen Activation ◽  
Amidolytic Activity ◽  
Surface Binding ◽  
Epidermal Growth ◽  
Fibronectin Type

AbstractFactor XII (FXII) zymogen activation requires cleavage after arginine 353 located in the activation loop. This cleavage can be executed by activated FXII (autoactivation), plasma kallikrein (PKa), or plasmin. Previous studies proposed that the activation loop of FXII is shielded to regulate FXII activation and subsequent contact activation. In this study, we aimed to elucidate this mechanism by expressing and characterizing seven consecutive N-terminally truncated FXII variants as well as full-length wild-type (WT) FXII. As soon as the fibronectin type II domain is lacking (FXII Δ1–71), FXII cleavage products appear on Western blot. These fragments display spontaneous amidolytic activity, indicating that FXII without the fibronectin type II domain is susceptible to autoactivation. Additionally, truncated FXII Δ1–71 is more easily activated by PKa or plasmin than full-length WT FXII. To exclude a contribution of autoactivation, we expressed active-site incapacitated FXII truncation variants (S544A). FXII S544A Δ1–71 is highly susceptible to cleavage by PKa, indicating exposure of the activation loop. In surface binding experiments, we found that the fibronectin type II domain is non-essential for binding to kaolin or polyphosphate, whereas the following epidermal growth factor-like domain is indispensable. Binding of full-length FXII S544A to kaolin or polyphosphate increases its susceptibility to cleavage by PKa. Moreover, the activation of full-length WT FXII by PKa increases approximately threefold in the presence of kaolin. Deletion of the fibronectin type II domain eliminates this effect. Combined, these findings suggest that the fibronectin type II domain shields the activation loop of FXII, ensuring zymogen quiescence.

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