ISSN:
1573-6881
Keywords:
Calcium-ATPase
;
Arrhenius behavior
;
sarcoplasmic reticulum
;
ATPase
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Physics
Notes:
Abstract Experiments were performed in which two batches of sarcoplasmic reticulum were isolated from rabbit hind leg muscle, one in the presence of dithiothreitol, the other in the absence of reducing agent. A comparative study was made of some of the properties of the two preparations, in particular, the Arrhenius behavior of the Ca2+-ATPase. The Ca2+-ATPase isolated in the absence of dithiothreitol is thermally unstable with the result that a triphasic Arrhenius plot was obtained. This triphasic behavior is largely the consequence of an uncoupling of the hydrolytic machinery from the calcium pump. In contrast, the sarcoplasmic reticulum preparation obtained in the presence of dithiothreitol is thermally stable and yields a linear Arrhenius plot. The difference in the Arrhenius behavior shown by the two preparations was abolished when the measurements of Ca2+-ATPase activity were made in the presence of the calcium ionophore, A23187.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00769731
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