[Interaction of ATP with sarcoplasmic reticulum Ca2+-ATPase; effect on the conformational state of the enzyme].
It was studied how temperature influences the NBD-Cl inactivation of sarcoplasmic reticulum Ca2+-ATPase and the protective effect of ATP under conditions preventing ATP hydrolysis. Two types of ATP-binding sites with Kd equal to 30 and 220 microM at 37 degrees C were found. ADP interacts with these sites with the (K'd = 20 and 200 microM). The temperature decrease from 25 degrees to 5 degrees C induces the abrupt increase in the Kd for the low affinity site. The possible reasons for heterogeneity of ATP-binding sites are discussed. The conclusion is made that interaction of monomers in oligomeric complex of Ca2+-ATPase induces heterogeneity of ATP-binding sites.
D009327:4-Chloro-7-nitrobenzofurazan / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D007700:Kinetics; D009132:Muscles / Q000201:enzymology; D011485:Protein Binding; D011487:Protein Conformation; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*; D013696:Temperature
D000255:Adenosine Triphosphate; D000252:Calcium-Transporting ATPases; D009327:4-Chloro-7-nitrobenzofurazan
Vzaimodeĭstvie ATP s Ca2+-ATP-azoĭ sarkoplazmaticheskogo retikuluma; vliianie na konformatsionnoe sostoianie fermenta.