本试剂盒应用双抗体夹心酶标免疫分析法测定标本中GAD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GAD、生物素化的抗人GAD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GAD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 total Human glutamic acid decarboxylase,GAD concentrations in cell culture supernates, serum, and plasma.
Introduction
Glutamate decarboxylase (GAD) is an enzyme that catalyzes the decarboxylation of glutamate to GABA and CO2. GAD uses PLP as a cofactor. In mammals, GAD exists in two isoforms encoded by two different genes - Gad1 and Gad2. These isoforms are GAD67 and GAD65 with molecular weights of 67 and 65 kDa, respectively. GAD1 and GAD2 are expressed in the brain where GABA is used as a neurotransmitter, GAD2 is also expressed in the pancreas. Glutamic acid decarboxylase (GAD65) is an enzyme that is produced primarily by pancreatic islet cells. A number of recent studies indicate that patients with insulin-dependent diabetes mellitus (IDDM) often have antibodies to GAD65 and several other islet cell antigens.
Both GAD67 and GAD65 are targets of autoantibodies in people who later develop insulin-dependent diabetes mellitus
Test principle
This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal antibody specific for GAD has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any GAD present is bound by the immobilized antibody. An enzyme-linked polyclonal antibody specific for GAD 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 GAD bound in the initial step. The color development is stopped and the intensity of the color is measured.
