Activation of human factor XI (plasma thromboplastin antecedent) by factor XIIa (activated Hageman factor)

Biochemistry ◽  
1977 ◽  
Vol 16 (26) ◽  
pp. 5831-5839 ◽  
Author(s):  
Kotoku Kurachi ◽  
Earl W. Davie
Keyword(s):  
Human Factor ◽  
Factor Xi ◽  
Hageman Factor ◽  
Factor Xiia

Pumpkin seed inhibitor of human factor XIIa (activated Hageman factor) and bovine trypsin

Biochemistry ◽  
1982 ◽  
Vol 21 (16) ◽  
pp. 3741-3746 ◽  
Author(s):  
Yoshio Hojima ◽  
Jack V. Pierce ◽  
John J. Pisano
Keyword(s):  
Human Factor ◽  
Pumpkin Seed ◽  
Hageman Factor ◽  
Bovine Trypsin ◽  
Factor Xiia

scholarly journals Factor XI activity and factor XI antigen in homozygous and heterozygous factor XI deficiency

Blood ◽  
1976 ◽  
Vol 48 (2) ◽  
pp. 165-174 ◽  
Author(s):  
A Rimon ◽  
S Schiffman ◽  
DI Feinstein ◽  
SI Rapaport
Keyword(s):  
Human Factor ◽  
Genetic Disorder ◽  
Family Members ◽  
Inhibition Assay ◽  
Factor Xi ◽  
Factor Xi Deficiency ◽  
Hereditary Factor ◽  
Normal Plasma ◽  
Antiserum Dilution ◽  
Standard Normal

A relatively potent antiserum against highly purified, unactivated human factor XI antigen was raised in a rabbit. This antiserum, after concentration, neutralized 50% of the factor XI clotting activity of a standard normal plasma at an antiserum dilution of 1/900. The antiserum was used in a neutralization-inhibition assay to study the relation between factor XI clotting activity and factor XI antigen in plasma from ten unrelated patients with homozygous factor XI deficiency and from 12 heterozygous family members of these patients. No evidence of factor XI antigen significantly in excess of factor XI activity was found in either group. All data to date have been consistent with the hypothesis that hereditary factor XI deficiency represents a genetic disorder resulting from the absence of factor XI molecule. Severity of bleeding in factor XI deficiency could not be correlated with the level of factor XI activity or factor XI antigen.

scholarly journals A Comparison of Murine and Human Factor XI

Blood ◽  
1997 ◽  
Vol 90 (3) ◽  
pp. 1055-1064 ◽  
Author(s):  
David Gailani ◽  
Mao-Fu Sun ◽  
Yuehui Sun
Keyword(s):  
Messenger Rna ◽  
Human Factor ◽  
Dextran Sulfate ◽  
Specific Activity ◽  
Expression System ◽  
Contact Activation ◽  
Factor Xi ◽  
Specific Expression ◽  
Factor Xi Deficiency ◽  
Mammalian Expression

Factor XI is a plasma glycoprotein that is required for contact activation initiated fibrin formation in vitro and for normal hemostasis in vivo. In preparation for developing a mouse model of factor XI deficiency to facilitate investigations into this protease's contributions to coagulation, we cloned the complementary DNA for murine factor XI, expressed the protein in a mammalian expression system, and compared its properties with human recombinant factor XI. The 2.8-kb murine cDNA codes for a protein of 624 amino acids with 78% homology to human factor XI. Both recombinant murine and human factor XI are 160 kD homodimers comprised of two 80 kD polypeptides connected by disulfide bonds. Murine factor XI shortens the clotting time of human factor XI deficient plasma in an activated partial thromboplastin time assay, with a specific activity 50% to 70% that of the human protein. In a purified system, murine factor XI is activated by human factor XIIa and thrombin in the presence of dextran sulfate. Murine factor XI differs from human factor XI in that it undergoes autoactivation slowly in the presence of dextran sulfate. This is due primarily to murine factor XIa preferentially cleaving a site on zymogen factor XI within the light chain, rather than the activation site between Arg371 and Val372. Northern blots of polyadenylated messenger RNA show that murine factor XI message is expressed, as expected, primarily in the liver. In contrast, messenger RNA for human factor XI was identified in liver, pancreas, and kidney. The studies show that murine and human factor XI have similar structural and enzymatic properties. However, there may be variations in tissue specific expression and subtle differences in enzyme activity across species.

A rapid enzyme-linked immunosorbent assay for human factor XI

1988 ◽  
Vol 50 (2) ◽  
pp. 329-334 ◽  
Author(s):  
Yutaka Komiyama ◽  
Hiroyuki Nishikado ◽  
Midori Masuda ◽  
Hiroshi Egawa ◽  
Norifumi Kobayashi ◽  
...  
Keyword(s):  
Immunosorbent Assay ◽  
Human Factor ◽  
Enzyme Linked Immunosorbent Assay ◽  
Factor Xi

scholarly journals Factor XI activity and factor XI antigen in homozygous and heterozygous factor XI deficiency

Blood ◽  
1976 ◽  
Vol 48 (2) ◽  
pp. 165-174 ◽  
Author(s):  
A Rimon ◽  
S Schiffman ◽  
DI Feinstein ◽  
SI Rapaport
Keyword(s):  
Human Factor ◽  
Genetic Disorder ◽  
Family Members ◽  
Inhibition Assay ◽  
Factor Xi ◽  
Factor Xi Deficiency ◽  
Hereditary Factor ◽  
Normal Plasma ◽  
Antiserum Dilution ◽  
Standard Normal

Abstract A relatively potent antiserum against highly purified, unactivated human factor XI antigen was raised in a rabbit. This antiserum, after concentration, neutralized 50% of the factor XI clotting activity of a standard normal plasma at an antiserum dilution of 1/900. The antiserum was used in a neutralization-inhibition assay to study the relation between factor XI clotting activity and factor XI antigen in plasma from ten unrelated patients with homozygous factor XI deficiency and from 12 heterozygous family members of these patients. No evidence of factor XI antigen significantly in excess of factor XI activity was found in either group. All data to date have been consistent with the hypothesis that hereditary factor XI deficiency represents a genetic disorder resulting from the absence of factor XI molecule. Severity of bleeding in factor XI deficiency could not be correlated with the level of factor XI activity or factor XI antigen.

scholarly journals The Apple 1 and Apple 4 domains of factor XI act synergistically to promote the surface-mediated activation of factor XI by factor XIIa

Blood ◽  
1995 ◽  
Vol 85 (8) ◽  
pp. 2078-2083 ◽  
Author(s):  
FA Baglia ◽  
FS Seaman ◽  
PN Walsh
Keyword(s):  
Binding Sites ◽  
Competitive Inhibitor ◽  
Amidolytic Activity ◽  
Factor Xi ◽  
Conformationally Constrained ◽  
Binding Factor ◽  
Factor Xiia ◽  
Noncompetitive Inhibitor ◽  
A1 Domain ◽  
Specific Sequences

Binding sites for high molecular weight kininogen (HK) and for factor XIIa are present in the Apple 1 (A1) and the A4 domains of factor XI, respectively. To define the roles of these two sites in surface-mediated factor-XI activation we prepared conformationally constrained synthetic peptides and recombinant A1 domain (rA1) and determined their effects on the activation of factor XI by factor XIIa in the presence of HK and either kaolin or dextran sulfate. Surface-mediated factor-XI activation by factor XIIa was inhibited by a conformationally constrained A4 peptide (Ala317-Gly350), by an A1 peptide (Phe56-Ser86), and by rA1 (Glu1-Ser90). When used in combination at equimolar concentrations, rA1 and A4 peptide were 10-fold more effective than either one alone in inhibiting surface-mediated activation of factor XI by factor XIIa. The A4 peptide was a competitive inhibitor of factor XIIa amidolytic activity and a noncompetitive inhibitor of factor-XI activation by factor XIIa, whereas rA1 and the A1 peptide did not inhibit factor XIIa. The rA1 domain inhibited factor XI binding to HK, whereas the A4 peptide did not. We conclude that specific sequences exposed on the surfaces of the A1 (Val59-Lys83) and A4 (Ala317-Gly350) domains of factor XI act synergistically to promote surface-mediated factor-XI activation by factor XIIa in the presence of HK by binding factor XI to surface-bound HK (A1 domain) and by binding factor XIIa near the cleavage site (Arg369-Ile370) of factor XI (A4 domain).

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