title: Effect of Mg2, ATP and some analogs on phosphorylase phosphatase from adrenal cortex.
abstract: The effect of Mg2, ATP and some of its analogs was studied on the spontaneously active and the ATP-Mg-dependent forms of phosphorylase phosphatase extracted from adrenal cortex. Inhibition of the spontaneously active form was observed with Mg2 (Ki - 9mM), ATP (Ki = 9micronM), 2'-doxy-ATP (Ki = 8 micronM), AtetraP (Ki = 9 micronM), AMP(CH2)PP (Ki = 11 micronM), ADP(CH2)P (Ki = 19 micronM), ADP(NH)P (Ki = 16micronM) and ADP (Ki = 25micronM). Activation of the ATP-Mg-dependent form was obtained with Mg2 (Ka = 0.55mM) (to a lower extent) and with ATP (Ka = 2micronM), 2'-deoxy-ATP (Ka = 6micronM) or AtetraP (Ka = 15micronM) in the presence of 0.5mM Mg2. Activation with AMP(CH2)PP was only observed in the presence of high concentrations (5mM) of Mg2 (Ka = 13micronM). No activation at all was observed with ADP(CH2)P or ADP(NH)P. Even though the activation of the ATP-Mg-dependent form does not seem to involve a kinase reaction, the stimulation by ATP or its analogs is rather specific, since it does not occur with analogs in which a methylene group or a nitrogen is substituted for the oxygen between the beta- and gamma-phosphates.
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000249:Adenosine Monophosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000302:Adrenal Cortex / Q000201:enzymology*; D000311:Adrenal Glands / Q000201:enzymology*; D006801:Humans; D066298:In Vitro Techniques; D008274:Magnesium / Q000494:pharmacology*; D010744:Phosphoric Monoester Hydrolases / Q000037:antagonists & inhibitors*; D010765:Phosphorylase Phosphatase / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D010765:Phosphorylase Phosphatase; D010744:Phosphoric Monoester Hydrolases; D008274:Magnesium