Molecular mechanism by which cyclic amp regulates myocardial contractility Page: 93 of 153
Pages: 142View a full description of this report.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
61
ATPase Activity
? +
Ca -dependent ATPase was measured in a manner similar to
that used by Tada et jfL (1974). Cardiac microsomes or the
isolated protein were suspended at a concentration of 30-50 yg/ml
in 40 mM histidine (pH 6.8), 0.125 M KC1, 5 mM NaN^, 5 mM MgC^
and varying calcium concentrations in the presence of EGTA. The
reaction was started by adding 5 mM [y- P]ATP (3yCi per
ymole). The final volume was 0.4 ml. The Ca -independent
ATPase activity was measured by including 0.5 mM EGTA instead of
calcium-EGTA in the reaction mixture. At various time intervals,
the reaction was stopped by adding 0.4 ml of ice-cold 13.33 mM
silicotungstic acid in 1.67 M H^O^. 0.3 ml of 10% ammonium
molybdate was added. After vortexing, 1 ml of isobutanol:benzene
(1:1) was added. The sample was vortexed for 30 sec, followed by
centrifugation at 1,000 x g for 10 min. 0.5 ml of the organic
phase was counted. To determine the nonspecific binding of
phosphate, controls were run by adding the protein to the reaction
px
mixture after the acid had been added. The free Ca
concentrations were determined by the method of Katz _et al_. (1970).
Isolation of the 22,000 Dalton Protein
Cardiac microsomes were suspended at a concentration of 7 mg/ml
in 0.25 M sucrose. A small aliquot of DOC was added at the ratio
of 2 yg D0C/7 mg microsomal protein (0.286 yg DOC/mg protein).
Upcoming Pages
Here’s what’s next.
Search Inside
This report can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Report.
Bidlack, J. M. Molecular mechanism by which cyclic amp regulates myocardial contractility, report, January 1, 1979; United States. (https://digital.library.unt.edu/ark:/67531/metadc1085147/m1/93/: accessed July 17, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.