预期应用
ELISA法定量测定人血清、血浆、细胞培养物上清或其它相关液体中PTK含量。
实验原理
本试剂盒应用双抗体夹心酶标免疫分析法测定标本中PTK水平。用纯化的抗体包被微孔板，制成固相抗体，往包被单抗的微孔中依次加入PTK抗原、生物素化的抗人PTK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PTK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 PTK concentrations in cell culture supernates, serum, and plasma.
Introduction
Protein tyrosine kinases (PTKs) play a key role in the regulation of cell proliferation, differentiation, metabolism, migration, and survival. They are classified as receptor PTKs and non-receptor PTKs. Receptor PTKs contain a single polypeptide chain with a transmembrane segment. The extracellular end of this segment contains a high affinity ligand-binding domain, while the cytoplasmic end comprises the catalytic core and the regulatory sequences. The cytosolic end also contains tyrosine residues, which become substrates or targets for the tyrosine kinase portion of the receptor. PTK remains inactive until a ligand binds to the receptor, which leads to the dimerization of two ligand-bound receptors (exception: insulin receptor). Once activated, receptors are able to autophosphorylate tyrosine residues outside the catalytic domain. This stabilizes the active receptor conformation and creates phosphotyrosine-docking sites for proteins that transduce signals within the cell. The cytosolic portion of the phosphorylated receptor recruits a number of cytosolic adapter proteins via interactions between phosphorylated tyrosine residues on the receptor and the SH2 domain on the adapter molecule. Different proteins have different SH2 domains that recognize specific phosphotyrosine residues. An SH2-containing protein, Grb2, acts as a common adapter protein in a majority of growth factor related signaling events.
Test principle
This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal
antibody specific for PTK has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any PTK present is bound by the immobilized antibody. An
enzyme-linked monoclonal antibody specific for PTK 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 PTK bound in the initial step. The color
development is stopped and the intensity of the color is measured.
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