title: Complexes of chromogranin A and dopamine beta-hydroxylase among the chromogranins of the bovine adrenal medulla.
abstract: 1. The core proteins of chromaffin granules have been examined by polyacrylamide gel electrophoresis and crossed immunoelectrophoresis against monospecific antisera. 2. Dopamine beta-hydroxylase (dopamine beta-monooxygenase, EC 1.14.17.1) appeared as the major immunogen of the core proteins and accounted for 4 and 8% by weight of the crude lysate and membrane-containing fractions, respectively. 3. The non-ionic detergent, Berol, solubilized dopamine beta-hydroxylase from the membranes in a form which was immunologically identical but of lower relative mobility by crossed immunoelectrophoresis. In the absence of detergent a difference in relative mobility was also noted between the purified enzyme and that contaminated by chromogranin A. These observations suggest that several molecular forms of dopamine beta-hydroxylase may occur which differ in size and/or charge due to interactions with the contaminants under the experimental conditions. 4. The main chromogranin in the crude lysate was absent from electropherograms of the acidic chromogranins (95--96% of total protein in lysate). These were obtained free of dopamine beta-hydroxylase by concanavalin A adsorption at high ionic strength or by acidification in 2 M acetic acid. The main band reappeared upon recombination with dopamine beta-hydroxylase, indicating the presence of some dopamine beta-hydroxylase, possibly as dimers, in this main, chromogranin A band. A protein concentration-dependent aggregate of dopamine beta-hydroxylase-free chromogranin A was detected, with a relative mobility slightly faster than the main band of the crude lysate.
mesh_terms: D000313:Adrenal Medulla / Q000201:enzymology*; D000818:Animals; D002417:Cattle; D002837:Chromaffin Granules / Q000201:enzymology*; D002838:Chromaffin System / Q000201:enzymology*; D002864:Chromogranins / Q000032:analysis; D004299:Dopamine beta-Hydroxylase / Q000032:analysis; D007123:Immunoelectrophoresis, Two-Dimensional; D046911:Macromolecular Substances; D009419:Nerve Tissue Proteins / Q000032:analysis
chemical_list: D002864:Chromogranins; D046911:Macromolecular Substances; D009419:Nerve Tissue Proteins; D004299:Dopamine beta-Hydroxylase