Figure. The binding activity of OC with FUR.Osteocalcin (OC), also known as bone gamma-carboxyglutamic acid-containing protein (BGLAP), is a noncollagenous protein hormone found in bone and dentin. Osteocalcin is secreted solely by osteoblasts and thought to play a role in the body's metabolic regulation and is pro-osteoblastic, or bone-building, by nature. It is also implicated in bone mineralization and calcium ion homeostasis. Osteocalcin acts as a hormone in the body, causing beta cells in the pancreas to release more insulin, and at the same time directing fat cells to release the hormone adiponectin, which increases sensitivity to insulin. Besides, Furin (FUR) has been identified as an interactor of OC, thus a binding ELISA assay was conducted to detect the interaction of recombinant mouse OC and recombinant mouse FUR. Briefly, OC were diluted serially in PBS, with 0.01% BSA (pH 7.4). Duplicate samples of 100mul were then transferred to FUR-coated microtiter wells and incubated for 2h at 37 degree C. Wells were washed with PBST and incubated for 1h with anti-OC pAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody, wells were aspirated and washed 3 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37 degree C. Finally, add 50uL stop solution to the wells and read at 450nm immediately. The binding activity of OC and FUR was shown in Figure 1, and this effect was in a dose dependent manner.