本试剂盒应用双抗体夹心酶标免疫分析法测定标本中钙结合蛋白水平。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钙结合蛋白、生物素化的抗小鼠钙结合蛋白抗体、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钙结合蛋白呈正相关。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 Mouse Calretinin, CR concentrations in cell culture supernates, serum, and plasma.
Introduction
Calretinin is a calcium-binding protein, 29 kDa, member of the family of so-called EF-hand proteins, to which also the S-100 proteins belong. Calretinin is abundantly expressed in neurons. Outside the nervous system, calretinin is found in mesothelial cells, steroid producing cells (adrenal cortical cells, testicular Leydig cells, ovarian theca interna cells), testicular Sertoli cells, rete testis, ovarian surface epithelium, some neuroendocrine cells, breast glands, eccrine sweat glands, hair follicular cells, thymic epithelial cells, endometrial stromal cells, and fat cells. In calretinin positive cells, the protein is generally found in both the cytoplasm and nuclei.
Calretinin is also considered an important diagnostic aid in the differential diagnosis of cystic and solid ameloblastic tumors. The rat and human calretinin exhibit 98% sequence homology and 91% homology to many other species. Calretinin is generally expressed with two other calcium binding proteins Calbindin D-29 and parvalbumin in CNS and other peripheral tissues. Two calcium binding proteins, calbindin and calretinin, have been reported to be expressed in abundance in Purkinje cells and other cell types in the cerebellum.
Calretinin is an intracellular calcium-binding protein belonging to the troponin C superfamily characterised by a structural motif described as the EF-hand domain. Calcium is an important moderator of a number of vital physiological processes, including neuronal excitability, axonal transport, synthesis and release of some neurotransmitters, membrane permeability and enzyme activity. Calretinin possesses six characteristic EF-hand structures of which five are able to bind calcium ions with high affinity. Calretinin is found in the nervous system and thymus. Calretinin can also be demonstrated at precise moments of the cell cycle, in particular, G1 phase and mitosis, and is associated with kinetochore microtubules which may indicate a role in chromosome separation.
Test principle
This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal antibody specific for Calretinin has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any Calretinin present is bound by the immobilized antibody. An enzyme-linked polyclonal antibody specific for Calretinin 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 Calretinin bound in the initial step. The color development is stopped and the intensity of the color is measured.
