Preparation and characterization of a colloidal gold-insulin complex with binding and biological activities identical to native insulinRM Smith, RI Goldberg and L Jarett Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia 19104. We studied the binding and biological activities of gold-insulin complexes to develop a complex with properties identical to native insulin. Stabilizing amounts of insulin absorbed to 5-, 10-, or 15-nm gold particles resulted in complexes with 40-327 insulin molecules per gold particle and 4-111 times the biological activity of unlabeled insulin, based on the molar concentration of gold complex. These data suggested that these complexes behaved as multivalent ligands. Gold- insulin complexes were prepared with 5% of the stabilizing insulin concentration and were stabilized with bovine serum albumin. This resulted in a complex with 5-7 insulin molecules per 10-nm gold particle, which stimulated glucose oxidation in rat adipocytes and competed with [125I]-insulin for binding to the insulin receptor identically to unlabeled insulin on an equimolar basis. The organization and distribution of insulin receptors occupied by this monovalent-behaving gold-insulin complex were virtually identical to previous observations using monomeric ferritin-insulin. Since multivalent ligands may affect receptor binding, re-distribution, and intracellular processing, the use of electron-dense probes that resemble the unlabeled ligand in biological and binding properties is appropriate when studying receptor dynamics of in vivo or in vitro biological systems. The gold-insulin complex developed in this study should serve this function.
Volume 36,
Issue 4,
pp. 359-365,
04/01/1988
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M. A. Rycyzyn, S. C. Reilly, K. OMalley, and C. V. Clevenger Role of Cyclophilin B in Prolactin Signal Transduction and Nuclear Retrotranslocation Mol. Endocrinol., August 1, 2000; 14(8): 1175 - 1186. [Abstract] [Full Text] |
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C. Clevenger, S. Altmann, and M. Prystowsky Requirement of nuclear prolactin for interleukin-2--stimulated proliferation of T lymphocytes Science, July 5, 1991; 253(5015): 77 - 79. [Abstract] [PDF] |
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