title: Cytochemical localization of adenylate cyclase.
abstract: This study examined 1) the effect of lead and fixation on adenylate cyclase activity, 2) the effect of lead on App(NH)p, and 3) the specificity of App(NH)p as a substrate for adenylate cyclase under the conditions of the cytochemical assay. The results indicated that: 1) fixation that provides adequate structural preservation inhibits enzyme activity to varying degrees depending on the tissue, fixative, length and temperature of fixation; 2) millimolar concentrations of lead do not negatively affect the adenylate cyclase activity of several different tissues (especially if 10 mM NaF is present); 3) lead does not cause the nonenzymatic hydrolysis of App(NH)p; 4) the App(NH)p obtained from the supplier is contaminated and should be purified before use, since lead can interact with the contaminants and this may be a source of error in the assay; and 5) adenylate cyclase appears to be the major enzyme that cleaves App(NH)p under cytochemical conditions.
mesh_terms: D000262:Adenylyl Cyclases / Q000032:analysis*; D000266:Adenylyl Imidodiphosphate; D000818:Animals; D001792:Blood Platelets / Q000201:enzymology; D002356:Cartilage / Q000201:enzymology; D002462:Cell Membrane / Q000201:enzymology*; D002645:Chickens; D006651:Histocytochemistry; D006801:Humans; D007854:Lead / Q000494:pharmacology; D051381:Rats; D013194:Staining and Labeling; D013363:Submandibular Gland / Q000201:enzymology
chemical_list: D000266:Adenylyl Imidodiphosphate; D007854:Lead; D000262:Adenylyl Cyclases