title: Effects of ADP and AMPPNP on the hydrogen-deuterium exchange kinetics in Ca2+, Mg2+-ATpase of sarcoplasmic reticulum.
abstract: The kinetics of the hydrogen-deuterium exchange reaction in sarcoplasmic reticulum (SR) membranes isolated from rabbit skeletal muscle was followed by infrared absorption measurements. The exchange rate in SR was much lower than that in the soluble proteins reported so far. When adenylyl-imidophosphate (AMPPNP, an TP analog) was present, the exchange rate was lower than that in free SR and it was the lowest when ADP was present. The effect of the nucleotides on the exchange rate reflects the conformational change of the Ca2+, Mg2+-ATpase of SR membranes on binding the nucleotides. The structure of e Ca2+, Mg2+-ATPase is more restricted in the following order: SR + ADP greater than SR + AMPPNP greater than free SR.
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives*; D000266:Adenylyl Imidodiphosphate / Q000494:pharmacology*; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D003903:Deuterium; D006859:Hydrogen; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011487:Protein Conformation / Q000187:drug effects; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*; D013055:Spectrophotometry, Infrared; D013696:Temperature
chemical_list: D000266:Adenylyl Imidodiphosphate; D000244:Adenosine Diphosphate; D006859:Hydrogen; D000255:Adenosine Triphosphate; D003903:Deuterium; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases