Fatty Acid Binding Protein 5 (FABP5) ,?is a 15-kDa cytosolic protein abundant in epidermal keratinocytes, macrophages, and adipocytes. As a member of the FABP family, it selectively binds long-chain fatty acids and retinoids, shuttling ligands to nuclear receptors to regulate gene transcription. In the skin, FABP5 drives epidermal differentiation and inflammation by modulating lipid mediator biosynthesis . It also acts as a redox sensor, protecting against oxidative stress in psoriasis and wound healing. Furthermore, the interaction between FABP5 and S100A7 augments pro-inflammatory signaling and cancer cell migration by orchestrating lipid-mediated pathways and inflammatory cytokine production.Thus a functional ELISA assay was conducted to detect the interaction of recombinant mouse FABP5 and recombinant human S100A7. Briefly,FABP5 was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to S100A7-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 mouse FABP5 and recombinant human S100A7 was shown in Figure 1, the EC50?for this effect is 0.447ug/mL.