Enzyme-linked immunoassay for study of sarcoplasmic reticulum adenosine triphosphatase

The immunological reactivity of isolated sarcoplasmic reticulum from rabbit fast muscle was tested with antibody to the Ca2+-pump protein which is the predominant component of these membranes. Microplate enzyme-linked immunoassay (ELISA) gave highly reproducible results under the conventional conditions used for checkerboard titration of soluble antigens and antibody. Parallel electron microscope observation of the incubated SR vesicles, negatively stained with ammonium molybdate, shows that the immunologically reactive form of the Ca2+-pump protein is still present in membrane-bound form.