The superfamily of secreted insulin-like growth factor (IGF) binding proteins includes high-affinity IGF binding proteins (IGFBP) and low-affinity binding proteins referred to as IGFBP-like or IGFBP- related proteins (IGFBPL, IGFBP-rP) (1). IGFBPs form complexes with IGF-I and -II, modulating their activity and bioavailability by modifying their binding to cell receptors, cell surfaces, and the extracellular matrix (1-5). In addition to direct effects on activity and binding of IGFs, IGFBPs actas carriers for circulating IGFs, prolonging their half-lives, and creating IGF reservoirs in tissues (1, 3, 4). IGFBP-2 and other superfamily members contain N-terminal IGF-binding domains with 12 conserved cysteines, and C-terminal thyroglobulin type 1 domains with 6 conserved cysteines (1). The C-terminal domain mediates heparin binding, which is enhanced in the presence of IGFs and, in the case of IGFBP-2, contains an RGD sequence that promotes integrin-mediated cell attachment (1, 3, 5-9). IGFBP-2 affinity and extracellular matrix binding enhancement is stronger for IGF-II than IGF-I (4, 9).
Intended Use:For the quantitative determination of Insulin-like Growth Factor Binding Protein 2 (IGFBP-2) concentrations in cell culture supernates, serum, plasma, and urine.
Sensitivity:0.09ng/ml
Range:~0.313-20ng/ml
Test Principle:This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal antibody specific for IGFBP-2 has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any IGFBP-2 present is bound by the immobilized antibody. After washing away any unbound substances, an enzyme-linked polyclonal antibody specific for IGFBP-2 is added to the wells. Following a wash to remove any unbound antibody-enzyme reagent, a substrate solution is added to the wells and color develops in proportion to the amount of IGFBP-2 bound in the initial step. The color development is stopped and the intensity of the color is measured.
Storage and Stability:Store other components at 4°C. Stable for at least 6 months For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.
