Neutralization of the Local Negative Charge Carried by Glycoprotein (GP)-Ib in Ristocetin-Induced Platelet Agglutination

Summary Pretreatment of platelets with chymotrypsin dose-dependently decreased glycoprotein (GP)-Ib amounts as measured by SDS- PAGE, ristocetin-induced agglutination and platelet electrophoretic mobility (EPM). Decrease in platelet EPM in response to 0.75 mg/ml ristocetin alone were 7.0 ± 2.3 and 6.8 ± 4.3% (M ± S.E., n = 6) for control and chymotrypsin-treated platelets, respectively (p >0.2). Von Willebrand factor (vWF) alone had no effect on platelet EPM. However, in the presence of 0.75 mg/ml ristocetin, added vWF (2.9 μg/ml) caused a further 6.3 ± 3.8% decrease in control platelet EPM, but caused no significant decrease in the enzyme-treated platelets (p >0.05). In the presence of 0.3 mg/ml ristocetin, added vWF (2.9-14.5 μg/ml) caused a small but significant decrease in control platelet EPM, but caused no significant decrease in the enzyme-treated platelets. These findings suggested that the GP-Ib carrying negative charge decreased by binding of vWF might facilitate a mutual approach of the GP-Ib molecules and bridge formation by vWF between different platelets.

[1]  H. Yamazaki,et al.  Role of platelet surface negative charge in ristocetin-induced platelet agglutination , 1982 .

[2]  S. M. Jung,et al.  Role of Surface Negative Charge in Platelet Function Related to the Hyperreactive State in Estrogen-Treated Prostatic Carcinoma , 1982, Thrombosis and Haemostasis.

[3]  A. McMichael,et al.  Monoclonal Antibody to Human Platelet Glycoprotein I II. EFFECTS ON HUMAN PLATELET FUNCTION , 1981, British journal of haematology.

[4]  A. McMichael,et al.  Monoclonal Antibody to Human Platelet Glycoprotein I I. IMMUNOLOGICAL STUDIES , 1981, British journal of haematology.

[5]  E. Kirby,et al.  The Effects Of Chymotrypsin And Of ADP On The Binding Site For Bovine Factor VIII On Human Platelets , 1981, Thrombosis and Haemostasis.

[6]  T. Motomiya,et al.  The Increase of the Electrophoretic Mobility of Platelets after Laparotomy , 1980, Thrombosis and Haemostasis.

[7]  T. Detwiler,et al.  Platelet thrombin receptors. Binding of alpha-thrombin is coupled to signal generation by a chymotrypsin-sensitive mechanism. , 1980, The Journal of biological chemistry.

[8]  J. T. ten Cate,et al.  Studies on the Mechanism of Ristocetin‐induced Platelet Aggregation: Binding of Factor VIII to Platelets , 1979, British journal of haematology.

[9]  D. Green,et al.  Platelet-Binding of the von Willebrand Factor , 1978, Thrombosis and Haemostasis.

[10]  B. Coller.  The effects of ristocetin and von Willebrand factor on platelet electrophoretic mobility. , 1978, The Journal of clinical investigation.

[11]  K. Mann,et al.  Purification of porcine and human ristocetin-Willebrand factor. , 1977, The Journal of laboratory and clinical medicine.

[12]  G. Jamieson,et al.  Platelet glycocalicin. I. Orientation of glycoproteins of the human platelet surface. , 1976, The Journal of biological chemistry.

[13]  Y. Sultan,et al.  Bernard-Soulier syndrome: a new platelet glycoprotein abnormality. Its relationship with platelet adhesion to subendothelium and with the factor VIII von Willebrand protein. , 1976, The Journal of laboratory and clinical medicine.

[14]  Kirby Ep.  Evans blue: a specific inhibitor of factor VIII-induced platelet agglutination. , 1975 .

[15]  E. Kirby,et al.  The interaction of bovine factor VIII with human platelets. , 1975, The Journal of clinical investigation.

[16]  J. Cazenave,et al.  Effects on platelet function of removal of platelet sialic acid by neuraminidase. , 1975, Laboratory investigation; a journal of technical methods and pathology.

[17]  D. Phillips,et al.  Platelet Membrane Glycoproteins Implicated in Ristocetin-Induced Aggregation , 1975, Thrombosis and Haemostasis.

[18]  R. Hutton,et al.  Hereditary Giant Platelet Syndrome: A Disorder of a New Aspect of Platelet Function , 1973, British medical journal.

[19]  D. Phillips.  Effect of trypsin on the exposed polypeptides and glycoproteins in the human platelet membrane. , 1972, Biochemistry.

[20]  J. W. Davis,et al.  The Effect of Neuraminidase on Platelet Aggregation Induced by ADP, Norepinephrine, Collagen or Serotonin , 1972, Thrombosis and Haemostasis.

[21]  L. Szabados,et al.  Changes in the aggregation of platelets enriched in sialic acid. , 1972, Nature: New biology.

[22]  J. Mustard,et al.  Preparation of Suspensions of Washed Platelets from Humans , 1972, British journal of haematology.

[23]  U. K. Laemmli,et al.  Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4 , 1970, Nature.

[24]  G. Seaman.  Surface potential and platelet aggregation. , 1967, Thrombosis et diathesis haemorrhagica. Supplementum.

[25]  O. H. Lowry,et al.  Protein measurement with the Folin phenol reagent. , 1951, The Journal of biological chemistry.