title: Adenylate cyclase of human parathyroid gland.
abstract: Experiments were performed on a particulate fraction from human parathyroid glands. A high activity of adenylate cyclase was detected which was linear with time and protein concentration. The enzyme had an optimum pH in the range of 7-8 and a Km for ATP of 0.44 X 10(-3) M. Ca++ had a profound inhibitory effect; a concentration of 0.5 mM Ca++ reduced enzyme activity by 60%. Maximal enzyme activity was obtained with 5 mM Mg++; higher concentrations of this cation also inhibited enzyme activity. The effect of Mn++ was similar to that of Mg++. Enzyme activity was stimulated by NaF, catecholamines, glucagon, and calcitonin. The effect of catecholamines seems to be mediated through beta-adrenergic receptors.
mesh_terms: D000236:Adenoma / Q000201:enzymology; D000262:Adenylyl Cyclases / Q000302:isolation & purification / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D010280:Parathyroid Glands / Q000201:enzymology*; D010282:Parathyroid Neoplasms / Q000201:enzymology; D012969:Sodium Fluoride / Q000494:pharmacology
chemical_list: D012969:Sodium Fluoride; D000262:Adenylyl Cyclases; D008274:Magnesium; D002118:Calcium