ISSN:
1573-6881
Keywords:
Sarcoplasmic reticulum
;
Ca2+, Mg2+-dependent ATPase
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Physics
Notes:
Abstract Two kinds of ATP binding sites were found on the ATPase molecule in deoxycholic acid-treated sarcoplasmic reticulum. One was the catalytic site (1 mol/mol active site) and its affinity was high. Upon addition of Ca2+, all the ATP bound to the catalytic site disappeared at 75 mM KCl, while a significant amount of ATP remained bound to the site at 0–2 mM KCl. The latter binding was found to be due to the formation of a slowly exchanging enzyme-ATP complex, which is in equilibrium with phosphoenzyme + ADP. The other binding site was the regulatory one (1 mol/mol active site) and its affinity was low, changing only insignificantly upon addition of Ca2+. The ATP binding to the regulatory site shifted the equilibrium between the slowly exchanging complex and EP toward EP.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00743060
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