Isolation of plasma co‐factor in adenosine diphosphate‐induced aggregation of bovine platelets

Suppression of the abnormally strong aggregation of washed platelets from bovine with serum albumin

“…Plasma cofactors participated in ADP-induced aggregation of unwashed platelets in Tris-ACD from bovine [7,10]. In the present study, an abnormally strong aggregation and disaggregation of washed platelets was observed by a simultaneous addition of serum albumin and ADP plus Ca 2÷.…”

“…wt 117 000, is highly effective in ADP-induced aggregation of unwashed platelets in Tris-ACD. Judging from the results obtained [7,10] and in the present studies, a scheme may be proposed as follows: Table 1 Suppresion of abnormally strong aggregation of washed platelets in Tris-ACD with native serum albumin Aggregability (~4max) When intact platelet was washed with Tris-ACD, plasma components such as serum albumin and plasma cofactors may be removed from the surface of platelet to form naked platelet (washed platelet), with the abnormally strong aggregability. Binding of naked platelet with serum albumin leads to coated platelet and further binding of plasma cofactors with coated platelet leads to intact platelet with the normal aggregability.…”

“…Three plasma cofactors from bovine blood, which participate essentially in ADP-induced aggregation of bovine platelets, were found [7,10]. One of the cofactors, with mol.…”

“…The concentration ofplatelets in each suspension was 3-5 X 10 s cells/ml. Aggregation of platelets was recorded spectrophotometrically as follows [7]: 50 gl 0.5 mM ADP containing 1.5 M CaC12 was added to 5 ml platelet suspension in a cylindrical photocell, preincubated for 10 min at 37°C. AA600 of sample suspension was recorded with time at 37°C under stirring at 1000 rev/min using a Simadzu recording spectrophotometer SV-50.…”

“…Crystalline bovine serum albumin was purchased from Kokusan Kagaku Co. Alkaline denatured serum albumin was obtained by incubating serum albumin at pH 13.1 for 2 h at room temperature. The plasma cofactors participating in ADP-induced aggregation of unwashed platelets in Tris-ACD from bovine were obtained as in [7,10]. was added to washed platelets in Tris-ACD preincubated with serum albumin (1.0 mg/ml for 0 min, 2 min, 5 min and 10 min, respectively.…”