Glucose and cyclic adenosine monophosphate stimulate activities of adenylate cyclase and guanylate cyclase of Tetrahymena pyriformis infusoria.
The sensitivities of cyclase enzymes adenylate cyclase and guanylate cyclase to glucose and extracellular cAMP were studied in Tetrahymena pyriformis infusoria. Glucose effectively stimulated activities of both cyclase enzymes, while cAMP more effectively stimulated adenylate cyclase. It was shown that [6-(14)C]glucose specifically bound to Tetrahymena pyriformis infusoria at dissociation constant (K(D)) and number of binding sites (B(max)) 43 nM and 7.53 fmol glucose per 100,000 cells and [8-(3)H]cAMP bound at 19 nM and 4.46 fmol cAMP per 100,000 cells, respectively. Hence, glucose and cAMP specifically bound to Tetrahymena pyriformis cells and stimulated activities of cyclases in these infusoria.
Laboratory of Molecular Endocrinology, I. M. Sechenov Institute of Evolutional Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia. alex_shpakov@list.ru
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D000262:Adenylyl Cyclases / Q000378:metabolism*; D001665:Binding Sites; D002250:Carbon Radioisotopes; D000242:Cyclic AMP / Q000378:metabolism / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology*; D006162:Guanylate Cyclase / Q000378:metabolism*; D007700:Kinetics; D015398:Signal Transduction; D013769:Tetrahymena pyriformis / Q000187:drug effects / Q000502:physiology*; D014316:Tritium
D002250:Carbon Radioisotopes; D014316:Tritium; D000242:Cyclic AMP; D000262:Adenylyl Cyclases; D006162:Guanylate Cyclase; D005947:Glucose