Transmembrane glycoprotein NMB is a protein that in humans is encoded by the GPNMB gene. In osteoblast progenitor cells, GPNMB works as a positive regulator of osteoblast differentiation during later stages of matrix maturation and mineralization that is mediated at least in part by BMP-2 in a SMAD1 dependent manner to promote osteoblast differentiation. GPNMB can enhance the repairing process in bone fracture, demonstrated by its high expression during chondrogenesis(soft callus) and osteogenesis(hard callus) compared to the intact femurs that is why Osteoactivin(OA) could be a novel therapeutic agent used to treat generalized osteoporosis or localized osteopenia during fracture repair by stimulating bone growth and regeneration. Similarly, GPNMB expression increases during osteoclast differentiation and it is functionally implicated in this process, possibly by promoting the fusion of osteoclast progenitor cells. Sample Type: Cell culture supernates, serum and plasma (heparin, EDTA) Intended Use: For quantitative detection of human GPNMB in cell culture supernates, serum and plasma (heparin, EDTA). Sensitivity: <10pg/ml Range: 156-10,000pg/ml Specificity: Natural and recombinant human GPNMB Test Principle: This human GPNMB BioAssay(TM) ELISA Kit was based on standard sandwich enzyme-linked immune-sorbent assay technology. A monoclonal antibody from mouse specific for GPNMB has been precoated onto 96-well plates. Standards(NSO, A22-P486) and test samples are added to the wells, a biotinylated detection polyclonal antibody from goat specific for GPNMB is added subsequently and then followed by washing with PBS or TBS buffer. Avidin-Biotin-Peroxidase Complex was added and unbound conjugates were washed away with PBS or TBS buffer. HRP substrate TMB was used to visualize HRP enzymatic reaction. TMB was catalyzed by HRP to produce a blue color product that changed into yellow after adding acidic stop solution. The density of yellow is proportional to the human GPNMB amount of sample captured in plate. Kit Components: 96-well plate precoated with human GPNMB antibody, 1 Lyophilized recombinant human GPNMB standard, 10ng/tube*2 Biotinylated human GPNMB antibody, 130ul (dilution 1:100) Avidin-Biotin-Peroxidase Complex (ABC), 130ul (dilution 1:100) Sample diluent buffer, 30ml Antibody diluent buffer, 12ml ABC diluent buffer, 12ml TMB color developing agent, 10ml TMB stop solution, 10ml Storage and Stability: Store powder at 4C liquid at -20C. Store other components at 4C. Stable for at least 6 months For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.
