Two-site immunoenzymometric assay for the 52-kDa cathepsin D in cytosols of breast cancer tissues.
Open Access
- 1 January 1989
- journal article
- research article
- Published by Oxford University Press (OUP) in Clinical Chemistry
- Vol. 35 (1) , 81-85
- https://doi.org/10.1093/clinchem/35.1.81
Abstract
We developed a solid-phase two-site immunoenzymometric assay (IEMA) of the estrogen-induced 52-kDa cathepsin D (EC 3.4.23.5) and its processed forms (48-kDa and 34-kDa proteins) in cytosols of breast cancer tissues, using two monoclonal antibodies directed against two different epitopes of these antigens. The first antibody is bound to a polystyrene microtiter well; the second is labeled with alkaline phosphatase. The assay involves a simultaneous incubation of the antigen with both antibodies, because we observed signal loss during sequential incubations. Alkaline phosphatase was chosen because other enzymes (peroxidase, beta-galactosidase) were inhibited by cytosol extraction buffers. The measurable range of 52-kDa-related proteins is from 0.3 to 6 nmol/L with precision (CVs) within and between runs of 3.9% and 15.8%, respectively. The sensitivity, accuracy, and rapid turnaround time of the two-site IEMA should facilitate the clinical evaluation of this new marker in oncology.This publication has 10 references indexed in Scilit:
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