Calcium-dependence of chromogranin A-catecholamine interaction.
Major components of the secretory organelle of bovine adrenal medullary cells, the chromaffin vesicles, are the acidic protein chromogranin A, catecholamines and Ca2+. The binding of Ca2+ to chromogranin A has been established. To study the interaction between chromogranin A and catecholamines and its dependence on Ca2+ we immobilized chromogranin A to a newly raised monoclonal antibody. It is shown that chromogranin A can bind (i) about 0.5 mol catecholamines per mol in a non-calcium-dependent manner and (ii) about 5 mol per mol in the presence of calcium. These results further support the notion that chromogranin A may act as a secretory granule-condensing protein.
Westermann
R
R
Department of Anatomy and Cell Biology, University of Marburg, FRG.
Stögbauer
F
F
Unsicker
K
K
Lietzke
R
R
D000313:Adrenal Medulla / Q000378:metabolism; D000818:Animals; D000911:Antibodies, Monoclonal; D002118:Calcium / Q000494:pharmacology*; D002417:Cattle; D053379:Chromogranin A; D002864:Chromogranins / Q000302:isolation & purification / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D004837:Epinephrine / Q000378:metabolism*; D015151:Immunoblotting; D007700:Kinetics; D009419:Nerve Tissue Proteins / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D053379:Chromogranin A; D002864:Chromogranins; D009419:Nerve Tissue Proteins; D002118:Calcium; D004837:Epinephrine