Alpha-2-Glycoprotein 1, Zinc-Binding (AZGP1), also known as zinc-α2-glycoprotein (ZAG), is a soluble protein belonging to the major histocompatibility complex (MHC) class I family. It is widely expressed in various bodily fluids and epithelial tissues. First identified in human plasma, AZGP1 exhibits multifunctional properties—most notably regulating lipid metabolism by stimulating lipolysis in adipocytes. As an important adipokine, it promotes fat breakdown and weight loss. Besides,Retinol Binding Protein 4 (RBP4) has been identified as an interactor of LOX, thus a functional binding ELISA assay was conducted to detect the interaction of recombinant human LOX and recombinant bovine RBP4. Briefly, LOX was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to RBP4-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-LOX pAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody for 1h at 37℃, wells were aspirated and washed 5 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37℃. Finally, add 50 µL stop solution to the wells and read at 450/630nm immediately. The binding activity of recombinant human LOX and recombinant bovine RBP4 was shown in Figure 1, the EC50 for this effect is 1.06 µg/mL..