Relative Importance Of Plasma Protease Inhibitors In The Inactivation Of Kallikrein In Human Plasma

1981 ◽  
Author(s):  
M Schapira ◽  
C F Scott ◽  
R W Colman
Keyword(s):  
Human Plasma ◽  
Antithrombin Iii ◽  
Plasma Concentrations ◽  
The Other ◽  
High Molecular Weight Kininogen ◽  
Physiological Conditions ◽  
First Order ◽  
Complete Inactivation ◽  
Important Regulator ◽  
Normal Human

Human plasma contains several inhibitors of plasma kallikrein (KAL), including C1-inhibitor (C1INH), α2-macro- globulin (α2M), antithrombin III (ATIII), and α1-antitrypsin (αlAT). Studies in purified systems have allowed us to quantitate the kinetic constants of each isolated inhibitor. We also have demonstrated that high molecular weight kininogen (HMWK) is an important regulator since it decreases the inactivation rate of KAL by all inhibitors except α2M. When purified inhibitors and HMWK are present at plasma concentrations, it can be calculated that C1INH, α2M, ATIII and α1AT account respectively for 49%, 49%, 0.8% and 0.2% of the KAL inhibitory activity. To assess if this prediction derived from purified system adequately describes the inhibition of KAL under more physiological conditions, we incubated KAL with normal human plasma (NHP), C1INH-deficient plasma (C1INH-D), and α2M-deficient plasma (α2M-D). KAL activity_was assessed using H-D-Pro-Phe-Arg- Nan as a substrate. C1INH-D was obtained from a patient with hereditary angioedema. C1INH in C1INH-D was 15% of the normal value as assessed by radial immunodiffusion. α2M-D was obtained by selective and complete inactivation of α2M by methylamine. The pseudo-first-order rate constants for the inactivation of_KAL by NHP, C1INH-D, α2M-D, and plasma deficient in both C1INH and α2M were respectively 8.8, 5.0, 5.5, and 1.8 S-1(×l03). Therefore, C1INH accounted for 63% of the observed inhibition, α2M for 35%, and all the other inhibitors for 2%. When these values were corrected for the concentration of HMWK, C1INH accounted for 47% of the inhibition, α2M for 51%, and all the other inhibitors for <2%. Thus, there is an excellent agreement between the results obtained when KAL is inhibited in purified systems and those obtained when it is inhibited in plasma. Moreover, these results indicate that C1INH and α2M are the only important inhibitors of KAL in NHP.

Blood Coagulation Inhibitor in a Snake Plasma (Bothrops jararaca)

1973 ◽  
Vol 30 (01) ◽  
pp. 106-113 ◽  
Author(s):  
Linda Nahas ◽  
Ferruccio Betti ◽  
Aura S. Kamiguti ◽  
Hissae Sato
Keyword(s):  
Human Plasma ◽  
Blood Coagulation ◽  
Antithrombin Iii ◽  
The Other ◽  
Normal Human Plasma ◽  
Clotting Time ◽  
Bovine Thrombin ◽  
Heat Stable ◽  
Coagulation Inhibitor ◽  
Normal Human

SummaryExperiments with plasmas samples from the snake B. jararaca and X. merremii have shown that the two differ markedly with respect to their reaction to bovine thrombin. The plasma of X. merremii appears to react in a manner very similar to that of normal human plasma both using the thrombin clotting test and using the antithrombin III assay of Astrup and Darling (Biggs and Macfariane 1962). The plasma of B. jararaca on the other hand, contains, in addition to antithrombin III, an inhibitor which resembles mammalian heparin. This inhibitor prolongs the thrombin clotting time of human and X. merremii plasmas, is recorded by the antithrombin assay and is neutralized by protamine. The inhibitor is however, not identical with mammalian heparin since it is not adsorbed by BaSO4 and Al(OH)3 (which adsorb heparin) and it is heat labil whereas mammalian heparin is heat stable.

scholarly journals New and rapid functional assay for C1 inhibitor in human plasma

Blood ◽  
1982 ◽  
Vol 59 (4) ◽  
pp. 719-724
Author(s):  
M Schapira ◽  
LD Silver ◽  
CF Scott ◽  
RW Colman
Keyword(s):  
Oral Contraceptive ◽  
Human Plasma ◽  
Order Rate Constant ◽  
Functional Assay ◽  
C1 Inhibitor ◽  
High Molecular Weight Kininogen ◽  
Excellent Correlation ◽  
First Order ◽  
Wide Range ◽  
Normal Human

C1 inhibitor (C1-INH) and alpha 2-macroglobulin (alpha 2M) account for over 90% of the inactivation of purified plasma kallikrein by normal human plasma. The rate of kallikrein inactivation is also dependent on the presence of high molecular weight kininogen (HMWK), which forms a reversible complex with kallikrein protecting the active site of the enzyme against inhibitors. By selectively inactivating alpha 2M with methylamine, and eliminating the protective effect of HMWK by dilution, the inactivation of kallikrein by plasma became almost exclusively dependent on C1-INH. Functional C1 inhibitor was assessed by measuring the pseudo-first-order rate constant for the inactivation of kallikrein by diluted methylamine-treated plasma in 29 individuals, including 11 controls, 11 oral contraceptive users, 5 patients with classical hereditary angioedema (HAE), and 2 patients with variant HAE. Over a wide range of concentrations, an excellent correlation (r = 0.90) was observed between functional and antigenic C1-INH among controls, oral contraceptive users, and patients with classical HAE. This new functional assay for C1-INH can be performed in less than 3 hr with commercially available reagents. Therefore, this assay will be helpful for the diagnosis and management of conditions associated with the deficiency of C1-INH, such as HAE.

scholarly journals New and rapid functional assay for C1 inhibitor in human plasma

Blood ◽  
1982 ◽  
Vol 59 (4) ◽  
pp. 719-724 ◽  
Author(s):  
M Schapira ◽  
LD Silver ◽  
CF Scott ◽  
RW Colman
Keyword(s):  
Oral Contraceptive ◽  
Human Plasma ◽  
Order Rate Constant ◽  
Functional Assay ◽  
C1 Inhibitor ◽  
High Molecular Weight Kininogen ◽  
Excellent Correlation ◽  
First Order ◽  
Wide Range ◽  
Normal Human

Abstract C1 inhibitor (C1-INH) and alpha 2-macroglobulin (alpha 2M) account for over 90% of the inactivation of purified plasma kallikrein by normal human plasma. The rate of kallikrein inactivation is also dependent on the presence of high molecular weight kininogen (HMWK), which forms a reversible complex with kallikrein protecting the active site of the enzyme against inhibitors. By selectively inactivating alpha 2M with methylamine, and eliminating the protective effect of HMWK by dilution, the inactivation of kallikrein by plasma became almost exclusively dependent on C1-INH. Functional C1 inhibitor was assessed by measuring the pseudo-first-order rate constant for the inactivation of kallikrein by diluted methylamine-treated plasma in 29 individuals, including 11 controls, 11 oral contraceptive users, 5 patients with classical hereditary angioedema (HAE), and 2 patients with variant HAE. Over a wide range of concentrations, an excellent correlation (r = 0.90) was observed between functional and antigenic C1-INH among controls, oral contraceptive users, and patients with classical HAE. This new functional assay for C1-INH can be performed in less than 3 hr with commercially available reagents. Therefore, this assay will be helpful for the diagnosis and management of conditions associated with the deficiency of C1-INH, such as HAE.

Analysis of Intrinsic Fibrinolysis in Human Plasma Induced by Dextran Sulfate

1992 ◽  
Vol 67 (04) ◽  
pp. 440-444 ◽  
Author(s):  
Hiroko Tsuda ◽  
Toshiyuki Miyata ◽  
Sadaaki Iwanaga ◽  
Tetsuro Yamamoto
Keyword(s):  
Molecular Weight ◽  
Human Plasma ◽  
Dextran Sulfate ◽  
Tissue Type ◽  
Factor Xii ◽  
Normal Human Plasma ◽  
High Molecular Weight Kininogen ◽  
Single Chain ◽  
Major Pathway ◽  
Normal Human

SummaryThe analysis of normal human plasma by fibrin autography revealed four species of plasminogen activator (PA) activity related to tissue-type PA, factor XII, prekallikrein and urokinase-type PA (u-PA). The u-PA activity increased significantly by incubating plasma with dextran sulfate. This increase was coincident with both the cleavage of factor XII and the complex formation of activated factor XII with its plasma inhibitors, which were determined by immunoblotting procedure. The dextran sulfate-dependent activation of u-PA required both factor XII and prekallikrein, but did not require either plasminogen or factor XI. High molecular weight kininogen was required only at a low concentration of dextran sulfate. Thus the results indicate that the factor XII and prekallikrein-mediated activation of single chain u-PA (scu-PA) operates as a major pathway of scu-PA activation in whole plasma in contact with dextran sulfate.

A Hitherto Undescribed Naturally Occurring Plasma Antagonist of Activated Factor X Inhibitor (Antithrombin III)

1979 ◽  
Author(s):  
E. T. Yin ◽  
W. J. Salsgiver ◽  
O. Tangen
Keyword(s):  
Equilibrium State ◽  
Human Plasma ◽  
Antithrombin Iii ◽  
Circumstantial Evidence ◽  
Incubation Mixture ◽  
Factor X ◽  
Normal Human Plasma ◽  
Plasma Component ◽  
Naturally Occurring ◽  
Normal Human

Circumstantial evidence suggested that normal human plasma contained a substance regulating the neutralization of F.Xa by F.Xa inhibitor(XaI), (Yin et.al.,Adv.Exper. Med. & Biol., 52 : 239, 1975, Plenum Press, N.Y.).This plasma component has now been isolated and partially purified in our laboratory, and tentatively designated as “Anti-XaI”.In experiments employing purified components, when Anti-XaI was incubated at 37°C with F.Xa, Xal and heparin for two minutes at pH7.5, the amount of F.Xa inhibited was inversely proportional to the Anti-XaI concentration. But, when the F.Xa was replaced by thrombin in the incubation mixture, the neutralization of thrombin clotting activity was undisturbed.Anti-XaI was found to be neither PF3 nor PF4.These and other data strongly suggest that the “Antithrombin III pathway” is more complex than currently believed to be. In circulating blood an equilibrium state must exist between Anti-XaI and XaI.Under certain conditions when the Anti-XaI activity is predominant the rate of F.Xa neutralization bv XaI then becomes slower than the activation of prothrombin to thrombin by F.Xa.

scholarly journals High molecular weight kininogen inhibits thrombin-induced platelet aggregation and cleavage of aggregin by inhibiting binding of thrombin to platelets

Blood ◽  
1991 ◽  
Vol 77 (3) ◽  
pp. 500-507 ◽  
Author(s):  
RN Puri ◽  
F Zhou ◽  
CJ Hu ◽  
RF Colman ◽  
RW Colman
Keyword(s):  
Molecular Weight ◽  
Platelet Aggregation ◽  
Plasma Concentration ◽  
Human Plasma ◽  
Shape Change ◽  
Dependent Manner ◽  
Normal Human Plasma ◽  
High Molecular Weight Kininogen ◽  
Normal Human ◽  
Dose Dependent

In this study we show that high molecular weight kininogen (HK) inhibited alpha-thrombin-induced aggregation of human platelets in a dose-dependent manner with complete inhibition occurring at plasma concentration (0.67 mumol/L) of HK. HK (0.67 mumol/L) also completely inhibited thrombin-induced cleavage of aggregin (Mr = 100 Kd), a surface membrane protein that mediates adenosine diphosphate (ADP)- induced shape change, aggregation, and fibrinogen binding. The inhibition of HK was specific for alpha- and gamma-thrombin-induced platelet aggregation, because HK did not inhibit platelet aggregation induced by ADP, collagen, calcium ionophore (A23187), phorbol myristate acetate (PMA), PMA + A23187, or 9,11-methano derivative of prostaglandin H2 (U46619). These effects were explained by the ability of HK, at physiologic concentration, to completely inhibit binding of 125I-alpha-thrombin to washed platelets. As a result of this action of HK, this plasma protein also completely inhibited thrombin-induced secretion of adenosine triphosphate, blocked intracellular rise in Ca2+ in platelets exposed to alpha- and gamma-thrombin, inhibited thrombin- induced platelet shape change, and blocked the ability of thrombin to antagonize the increase in intracellular cyclic adenosine monophosphate (cAMP) levels induced by iloprost. Because elevation of cAMP is known to inhibit binding of thrombin to platelets, we established that HK did not increase the intracellular concentration of platelet cAMP. Finally, HK did not inhibit enzymatic activity of thrombin. To study the role of HK in the plasma environment, we used gamma-thrombin to avoid fibrin formation by alpha-thrombin. Platelet aggregation induced by gamma- thrombin was also inhibited by HK in a dose-dependent manner. The EC50 (concentration to produce 50% of the maximum rate of aggregation) of gamma-thrombin for washed platelets was 7 nmol/L and increased to 102 nmol/L when platelets were suspended in normal human plasma. The EC50 for platelet aggregation induced by alpha-thrombin in plasma deficient in total kininogen was 40 nmol/L. When supplemented with HK at plasma concentration (0.67 mumol/L), the EC50 increased to 90 nmol/L, a value similar to that for normal human plasma. These results indicate that (1) HK inhibits thrombin-induced platelet aggregation and cleavage of aggregin by inhibiting binding of thrombin to platelets; (2) HK is a specific inhibitor of platelet aggregation induced by alpha- and gamma- thrombin; and (3) HK plays a role in modulating platelet aggregation stimulated by alpha-thrombin in plasma.

The Contribution of Plasma Protease Inhibitors to Antiplasmin Activity in Man

1976 ◽  
Vol 51 (2) ◽  
pp. 215-218
Author(s):  
G. P. M. Crawford ◽  
D. Ogston ◽  
A. S. Douglas
Keyword(s):  
Human Plasma ◽  
Protease Inhibitors ◽  
Trypsin Inhibitor ◽  
Antithrombin Iii ◽  
The Other ◽  
Plasmin Activity ◽  
Neutralizing Activity ◽  
Α2 Macroglobulin

1. Human plasma contains a variety of proteins that are capable of inhibiting plasmin activity. Whole plasma possesses ‘rapid’ and ‘progressive’ plasmin-neutralizing activity: this study assesses the contribution of individual protease inhibitors to this plasmin-neutralizing property of plasma. 2. Rapid and progressive antiplasmin activities of human plasma correlate with α2-macroglobulin and α1-antitrypsin concentrations respectively. 3. Fluctuations in the amounts of the other measured inhibitors (antithrombin III, Cl inactivator and inter-α-trypsin inhibitor) did not influence the measured antiplasmin activity.

The Determinant of the Prothrombin Time in Normal Human Plasma

1958 ◽  
Vol 02 (03/04) ◽  
pp. 226-235 ◽  
Author(s):  
Armand J. Quick
Keyword(s):  
Prothrombin Time ◽  
Human Plasma ◽  
Active State ◽  
The Other ◽  
Normal Adult ◽  
Normal Human Plasma ◽  
Prolonged Prothrombin Time ◽  
Adult Human ◽  
Plasma Factor ◽  
Normal Human

SummaryNormal adult human plasma has a constant prothrombin time when determined under standardized conditions and with carefully prepared reagents. An explanation for this constancy is offered; namely, that a plasma factor, designated as “prothrombin time fixing agent” (PTFA), is responsible for maintaining a constant fraction of the total prothrombin in the active state. This fraction is measured quantitatively by the prothrombin time, while the inactive prothrombin or prothrombinogen, has no influence on the test. The concentration of PTFA is fixed by heredity and appears to be a dominant. The results of studies on two subjects, one with true hypoprothrombinemia, the other with a prolonged prothrombin time but a normal total prothrombin and no deficiency of accessory prothrombin factors are reported and interpreted according to this hypothesis. A deficiency of PTFA can be differentiated from all other known hypoprothrombinemic states by observing a prolonged prothrombin time when mixing the plasma with an equal volume of fresh normal plasma.

scholarly journals Human antithrombin III heterogeneity

Blood ◽  
1981 ◽  
Vol 57 (2) ◽  
pp. 229-232 ◽  
Author(s):  
L Williams ◽  
G Murano
Keyword(s):  
Human Plasma ◽  
Antithrombin Iii ◽  
Agarose Gel ◽  
Normal Human Plasma ◽  
Congenital Deficiency ◽  
Single Donor ◽  
At Iii ◽  
Normal Human

Abstract Crossed immunoelectrophoretic patterns were obtained on three patients with a congenital deficiency of anti-thrombin III (AT-III), and on normal single donor and “pooled” plasma controls. In the presence of heparin (incorporated into the agarose gel matrix), the AT-III of normal human plasma was separated into four components: two major, faster-moving components, and two minor, slower-moving components. The three patients with congenital deficiency of AT-III (levels approximately 50% of normal) appeared to possess only one of the faster- moving components, and one of the slower-moving components.

Sign in / Sign up

Export Citation Format

Share Document