Calmodulin binding to secretory granules isolated from bovine neurohypophyses.
Secretory granules, isolated from bovine neurohypophyses on isoosmolar Percoll-sucrose-EGTA gradients had a calmodulin content of 0.09 +/- 0.01 micrograms/mg protein (SE, n = 6). The distribution of calmodulin on the gradient showed that it did not copurify with the granules. Specific binding sites for calmodulin with a high affinity (Kd = 2.43 +/- 0.27 X 10(-9) M (SE, n = 5] and a maximum binding capacity of 1.3 +/- 0.4 pmol/mg protein (SE, n = 5) could be demonstrated when such secretory granules were incubated with 125I-calmodulin.
D000818:Animals; D001665:Binding Sites; D002147:Calmodulin / Q000302:isolation & purification / Q000378:metabolism*; D002148:Calmodulin-Binding Proteins; D002417:Cattle; D003594:Cytoplasmic Granules / Q000378:metabolism*; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010904:Pituitary Gland, Posterior / Q000032:analysis*
D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D010749:Phosphoprotein Phosphatases