Osteocalcin ELISA Kit: Gla-Type Osteocalcin (Gla-OC) EIA Kit

The Takara Bio Osteocalcin ELISA Kit offers sensitive detection of the osteogenic marker osteocalcin (OC). OC, also known as gamma-carboxyglutamic acid protein, is a small (5.9 kDa), vitamin K-dependent, hydroxyapatite (Ca2+)-binding protein synthesized exclusively by osteoblasts and odontoblasts. The tissue-specific expression of OC makes it an excellent osteogenic marker for measuring osteoblast activity during bone formation. Osteocalcin is also a hormone that controls the regulation of glucose and fat deposition and plays a role in male fertility. Three gamma-carboxyglutamic acid (Gla) residues at positions 17, 21, and 24 of the protein are responsible for binding calcium. OC calcium-binding is also required for such biological activities as activation of the blood coagulation cascade. Carboxylated OC (Gla-OC) is most likely the active form of the protein, while decarboxylated OC (Glu-OC), which has weak hydroxyapatite affinity, represents the inactive form. Gla-OC versus Glu-OC serum levels correlate well with bone formation; thus, the Takara Bio human osteocalcin ELISA kit provides a better analysis of bone growth and remodeling than conventional assays that do not differentiate between the active and inactive protein forms.

The Gla-Type Osteocalcin (Gla-OC) EIA Kit is a 96-well in vitro enzyme immunoassay kit for the quantitative determination of human Gla-OC in serum, cultured cell extract, cell culture supernatant and other biological fluids. It is a solid phase sandwich EIA utilizing two mouse monoclonal Gla-OC antibodies, one of which is coated onto the plate, and the other of which is peroxidase-labeled. This assay format permits highly sensitive detection of Gla-OC using the following two-step incubation method: In the first step, biological samples are incubated in the antibody-coated microtiter plate; in the second step, the plate is washed and incubated with the peroxidase-labeled Gla-OC antibody. A substrate is added and the reaction between the peroxidase and substrate (H2O2, TMBZ) results in color development. The amount of sample Gla-OC is determined by absorbance measurement using an EIA plate reader. Accurate Gla-OC sample concentration can be determined by comparing its specific absorbance with that of the supplied standard on a standard curve.