本试剂盒应用双抗体夹心酶标免疫分析法测定标本中ER水平。用纯化的抗体包被微孔板，制成固相抗体，往包被抗体的微孔中依次加入ER抗原、生物素化的抗人ER抗体、HRP标记的亲和素，经过彻底洗涤后用底物TMB显色。TMB在过氧化物酶的催化下转化成蓝色，并在酸的作用下转化成最终的黄色。颜色的深浅和样品中的ER呈正相关。用酶标仪在450nm波长下测定吸光度（OD值），计算样品浓度。
Intended use
This immunoassay kit allows for the specific measurement of human Estrogen Receptor,ER concentrations in cell culture supernates, serum, and plasma.
Introduction
The estrogen receptor (ER) is a member of the nuclear hormone family of intracellular receptors which is activated by the hormone 17 β-estradiol.The main function of the estrogen receptor is as a DNA binding transcription factor which regulates gene expression. However the estrogen receptor also has additional functions independent of DNA binding.
There are two different forms of the estrogen receptor usually referred to as α and β each encoded by a separate gene (ESR1 and ESR2 respectively). Hormone activated estrogen receptors form dimers, and since the two forms are coexpressed in many cell types, the receptors may form ERα (αα) or ERβ (ββ) homodimers or ERαβ (αβ) heterodimers.Estrogen receptor alpha and beta show significant overall sequence homology, and both are composed of seven domains.The ERα is found in endometrium, breast cancer cells, ovarian stroma cells and in the hypothalamus.The expression of the ERβ protein has been documented in kidney, brain, bone, heart,lungs, intestinal mucosa, prostate, and endothelial cells. While they both bind estrogen as well as other agonists and antagonists, the two receptors have distinctly different localizations and concentrations within our body. Structural differences also exist between the two. The ER ligands tamoxifen, raloxifene, and ICI-164384 were activators with Erβ as well as ERα, although the degree of agonism differed between cell types. These molecules are examples of SERM’s, selective estrogen receptor modulators. Thus, the role of estrogen complexed to ERβ appears to be to turn off transcription of these genes, whereas the SERMs may override this blockade and activate gene transcription.
Estrogen receptor structure-function is a vast topic and the subject of very active current research. Nuclear receptors are a large family of structurally related ligand-inducible transcription factors, including steroid receptors (SRs), thyroid/retinoids receptors (TR, RARs and RXRs), vitamin D receptors (VDR), LXR, PPARs, estrogen receptors (ERα and ERβ), and orphan receptors for which no ligand has been yet identified. While having in common a modular structure, they are activated by distinct lipophilic small molecules such as glucocorticoids, progesterone, estrogens, retinoids, and fatty acid derivatives.All nuclear receptors have a hydrophobic pocket into which its specific ligand binds, with helix 12 (H12) being the key response element of NRs. When an agonist is bound to a NR, H12 is oriented anti-parallel to H11, capping the ligand binding pocket.
Test principle
This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal
antibody specific for Estrogen Receptor has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any Estrogen Receptor present is bound by the immobilized antibody. An enzyme-linked polyclonal antibody specific for Estrogen Receptor 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 Estrogen Receptor bound in the initial step. The color development is stopped and the intensity of the color is measured.
