title: Specificity and properties of the nucleotide carrier in chromaffin granules from bovine adrenal medulla.
abstract: 1. The influence of various substances on the uptake of [3H]ATP and [14C]-noradrenaline into isolated bovine chromaffin granules was investigated. The carrier-mediated [3H]ATP uptake is specifically inhibited by SO42-, PO43- and phosphoenolpyruvate. Compounds with carboxylic acid or sulphonic acid groups had no significant inhibitory effects on either uptake. 2. 35SO42-, 32PO43- and phosphoenol[14C]pyruvate are taken up into chromaffin granules by a temperature-dependent process that is inhibited by atractyloside, uncouplers of oxidative phosphorylation and lipid-permeant anions. The apparent Km of 35SO42- uptake is 0.4 mM. 3. These results indicate that the nucleotide carrier in chromaffin granules has a broad specificity, transporting compounds with two strong negative charges. 4. Amino acid probes influence the uptake of ATP and catecholamines differently. Pyridoxal phosphate inhibits both uptake processes, 4,4'-di-isothiocyanostilbene-2,2'-disulphonic acid preferentially blocks ATP uptake, whereas phenylglyoxal blocks only ATP transport. It is suggested that the nucleotide carrier possesses arginine residues in a functionally important position. 5. The significance of these results obtained on isolated granules for the function of chromaffin granules within the cell is discussed.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000313:Adrenal Medulla / Q000378:metabolism*; D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D001693:Biological Transport, Active / Q000187:drug effects; D002417:Cattle; D002837:Chromaffin Granules / Q000187:drug effects / Q000378:metabolism*; D002838:Chromaffin System / Q000378:metabolism*; D007700:Kinetics; D000226:Mitochondrial ADP, ATP Translocases / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism; D009713:Nucleotidyltransferases / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D010728:Phosphoenolpyruvate / Q000378:metabolism; D013431:Sulfates / Q000378:metabolism
chemical_list: D000596:Amino Acids; D010710:Phosphates; D013431:Sulfates; C012036:sodium sulfate; D010728:Phosphoenolpyruvate; D000255:Adenosine Triphosphate; D000226:Mitochondrial ADP, ATP Translocases; D009713:Nucleotidyltransferases; D009638:Norepinephrine