Generation Of Platelet Aggregating Activity By Adsorption Of Low-Molecular-Weight Factor VIII- Related Protein To Colloidal Gold

1981 ◽  
Author(s):  
M Furlan ◽  
M Horisberger ◽  
B A Perret ◽  
E A Beck
Keyword(s):  
Molecular Weight ◽  
Factor Viii ◽  
Human Platelets ◽  
Reduction Factor ◽  
Low Molecular Weight ◽  
Weight Factor ◽  
Related Protein ◽  
Gold Particles ◽  
Disulfide Reduction ◽  
Human Factor Viii

Both the ristocetin cofactor (VIII:Rcof) and the platelet aggregating factor (PAF) are preferentially associated with the largest complexes of human and bovine factor VIII, respectively. It is not known whether the functional deficiency of smaller species of factor VIII is due to their size or quality. Binding of small oligomers of factor VIII-related protein, isolated by gel filtration from cryoprecipitates or prepared by disulfide reduction of multimeric factor VIII, onto gold granules (diameter 20-30 nm) generated platelet aggregating activity; on the other hand, adsorption of large factor VIII multimers onto gold particles impaired the initially high VIII: Rcof and PAF. Aggregation of human platelets by human factor VIII-coated gold particles required ristocetin and was not competitively inhibited by unbound low-molecular-weight factor VIII. We conclude that essential properties of factor VIII, necessary for its “von Willebrand activity”, are present potentially in the smallest species recovered from plasma or even after disulfide reduction. Factor VUI-coated gold granules can be used as an electron-dense label for surface receptors for factor VIII on human platelets.

Absence of the 145,000 Molecular Weight, Soluble Platelet Membrane Glycoprotein - Lack of Platelet Agglutination

1979 ◽  
Vol 42 (05) ◽  
pp. 1626-1629 ◽  
Author(s):  
Nils Olav Solum ◽  
Inger Hagen ◽  
Miroslav Peterka ◽  
Torbjørn Gjemdal
Keyword(s):  
Molecular Weight ◽  
Factor Viii ◽  
Human Platelets ◽  
Platelet Membrane ◽  
Membrane Glycoprotein ◽  
Related Protein ◽  
Giant Platelets ◽  
Platelet Membrane Glycoprotein ◽  
Human Factor Viii ◽  
Bovine Factor

SummaryOne step in the function of platelets in hemostasis is their adhesion to subendothelial tissue. The human factor VIII related protein (von Willebrand factor) is considered to be involved in the adhesion phenomenon (Baumgartner et al. 1977). One manifestation of the protein-cell interaction can be observed as a platelet agglutination after addition to the human platelets of a combination of the human protein and the glycopeptide ristocetin, or after addition of the bovine protein alone. The bovine factor VIII related protein as such directly binds to the platelet membrane (Kirby and Sha May Tang 1977) and thus represents a simpler system than ristocetin plus the human cofactor which may have to interact with each other before excerting their effect on the platelet membrane. The present paper concerns the se.One of the characteristics of the agglutination of human platelets brought about by the bovine factor VIII related protein (as well as by ristocetin plus the human cofactor) is that it is independent of the energy metabolism and the internal organization of the platelet. One would therefore expect that modified platelets and platelet “ghosts” would agglutinate as long as certain structures on the outer cell surface are chemically and sterically intact. Because of the hydrophilic character of the carbohydrate side chains, the membrane glycoproteins are considered of special importance for cell contact phenomena. Thus it has already been known for some years that giant platelets of the Bernard-Soulier type which do not agglutinate with the bovine protein (Bithell et al. 1972), contain a reduced amount of sialic acid related to protein content and surface area (Grottum and Solum 1969), and show a reduced glycoprotein stain in the GP I region on SDS polyacrylamide gel electrophoresis (Nurden and Caen 1975).This paper presents five observations which support a working hypothesis stating that the presence on the platelet membrane of the 145,000 molecular weight, soluble platelet membrane glycoprotein called GPS or glycocalicin is a prerequisite to the agglutination of human platelets by bovine factor VIII related protein.

LOW-MOLECULAR-WEIGHT FACTOR VIII

The Lancet ◽  
1973 ◽  
Vol 301 (7810) ◽  
pp. 1000-1001 ◽  
Author(s):  
A.L. Bloom ◽  
J.C. Giddings ◽  
I.R. Peake ◽  
HarveyJ. Weiss ◽  
B.N. Bouma ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Factor Viii ◽  
Low Molecular Weight ◽  
Weight Factor

scholarly journals Rabbit factor VIII: identification of size heterogeneity

Blood ◽  
1977 ◽  
Vol 49 (2) ◽  
pp. 209-217
Author(s):  
ME Rick ◽  
DE Wampler ◽  
LW Hoyer
Keyword(s):  
Molecular Weight ◽  
Ionic Strength ◽  
Factor Viii ◽  
Low Molecular Weight ◽  
Gel Chromatography ◽  
Weight Factor ◽  
Rabbit Plasma ◽  
Factor Viii Activity ◽  
Size Heterogeneity ◽  
Two Peaks

Two forms of rabbit factor VIII procoagulant activity, distinguishable by size on gel filtration and ultracentrifugation, have been identified in normal rabbit plasma. These studies have been carried out with citrate-anticoagulated rabbit plasma obtained by cardiac puncture. Two peaks of factor VIII activity were obtained on agarose gel chromatography, using physiologic ionic strength buffers: a high molecular weight peak eluting at the void volume and a second peak eluting with smaller plasma proteins. The presence of high and low molecular weight factor VIII activities was confirmed by sucrose density gradient centrifugation. The two peaks of factor VIII activity remained distinct when proteolytic inhibitors were added to the plasma and eluting buffers. Both the high and low molecular weight factor VIII procoagulant activities were inhibited by antibodies to human and rabbit factor VIII, and both were activated by thrombin. The identification of size heterogeneity of factor VIII in normal rabbit plasma, in the absence of any modification by ionic strength, may permit more satisfactory study of the relationship of factor VIII size to function.

Characterization of Low Mololecular Weight Factor VIII.

1979 ◽  
Author(s):  
G. Rock ◽  
D. Palmer ◽  
E. Kang ◽  
G. Jamieson ◽  
W. Cruickshank
Keyword(s):  
Molecular Weight ◽  
Factor Viii ◽  
Polyacrylamide Gel Electrophoresis ◽  
Structural Features ◽  
Protein Characterization ◽  
Low Molecular Weight ◽  
Weight Factor ◽  
High Molecular Weight Complex ◽  
Peptide Map ◽  
Polyethylene Glycol Precipitation

The high molecular weight complex of Factor VIII was isolated from resolubilized cryoprecipitate by polyethylene glycol precipitation followed by chromatography on Bio Gel A15M. Upon rechromatography of this compound in buffer containing 1M NaCl and 1mM benzamidine the low molecular weight sub-unit possessing the procoagulant activity eluted at a volume of 2.3V. SDS polyacrylamide gel electrophoresis of this material in 5% acrylamide gave a single band whose Rf indicated a molecular weight of 150,000. The isoelectric point was determined to be 7.4. A peptide map of pepsin digested, I125 labelled material showed very few peptides which were radioactive and/or fluorescamine positive; as well, there was a relatively large amount of radioactive, non-fluorescamine positive material which was slow moving on pH 2.1 electrophoresis and immobile on chromatography. Amino acid analysis yielded data consistent with the presence of a small amount of protein. Carbohydrate analysis indicated a large amount of neutral hexoses, a very small amount of hexosamines and no detectable sialic acid. These results suggest that the structural features of low molecular weight Factor VIII may account for its anomalous behaviour in standard protein characterization procedures.

LOW-MOLECULAR-WEIGHT FACTOR VIII

The Lancet ◽  
1973 ◽  
Vol 301 (7807) ◽  
pp. 827-828 ◽  
Author(s):  
F. Nouk-Eldin ◽  
MariaBenedetta Donati ◽  
Giovanni De Gaetano ◽  
Jozef Vermylen
Keyword(s):  
Molecular Weight ◽  
Factor Viii ◽  
Low Molecular Weight ◽  
Weight Factor

LOW-MOLECULAR-WEIGHT FACTOR VIII

The Lancet ◽  
1973 ◽  
Vol 301 (7804) ◽  
pp. 661-662 ◽  
Author(s):  
A.L. Bloom ◽  
J.C. Giddings ◽  
I.R. Peake
Keyword(s):  
Molecular Weight ◽  
Factor Viii ◽  
Low Molecular Weight ◽  
Weight Factor

Von Willebrand Activity of Low Molecular Weight Human Factor VIII Increases by Binding to Gold Granules

1981 ◽  
Vol 45 (03) ◽  
pp. 242-246 ◽  
Author(s):  
Miha Furlan ◽  
Beat A Perret ◽  
Eugene A Beck
Keyword(s):  
Molecular Weight ◽  
Factor Viii ◽  
Human Factor ◽  
Low Molecular Weight ◽  
Human Factor Viii ◽  
Large Factor ◽  
Cofactor Activity ◽  
Von Willebrand ◽  
Ristocetin Cofactor ◽  
Ristocetin Cofactor Activity

SummaryHuman factor VIII/von Willebrand protein is a population of multimers which vary in size but contain apparently identical subunits. Large-molecular-weight forms possess higher ristocetin cofactor/von Willebrand activity than the native smaller oligomers. Disulfide reduction of large factor VIII multimers results in progressively decreasing molecular size and a loss of ristocetin cofactor activity. Small molecular forms of factor VIII were adsorbed onto gold granules (average diameter 20-30 nm) and thereby increased their ristocetin cofactor activity. The amount of adsorbed material and the extent of activation were dependent on the pH of the colloid suspension. The maximum recovery of von Willebrand activity was observed at pH 4.75. Aggregation of fixed human platelets by factor VIII-coated gold particles was dependent on ristocetin concentration and was not competitively inhibited by unbound low-molecular-weight factor VIII. These results suggest that the subunits of the native small factor VIII species possess potential binding affinity for platelet receptors, which is manifested following formation of large factor VIII polymers. We conclude that an optimal size of remarkably high molecular weight is required for efficient aggregation of platelets by factor VIII as occurs during the primary phase of hemostasis.

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