Apolipoprotein C3 (AP°C3) also known as apo-CIII is a component of very low density lipoprotein (VLDL). AP°C3 inhibits lipoprotein lipase and hepatic lipase; it is thought to inhibit hepatic uptake of triglyceride-rich particles. An increase in ap°C-III levels induces the development of hypertriglyceridemia. Some evidences suggest an intracellular role for Apo-CIII in promoting the assembly and secretion of triglyceride-rich VLDL particles from hepatic cells under lipid-rich conditions. Besides, Prenylcysteine Oxidase 1 (PCYOX1) has been identified as an interactor of AP°C3, thus a binding ELISA assay was conducted to detect the interaction of recombinant mouse AP°C3 and recombinant mouse PCYOX1. Briefly, AP°C3 were diluted serially in PBS, with 0.01% BSA (pH 7.4). Duplicate samples of 100μL were then transferred to PCYOX1-coated microtiter wells and incubated for 2h at 37°C. Wells were washed with PBST and incubated for 1h with anti-AP°C3 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°C. Finally, add 50µL stop solution to the wells and read at 450nm immediately. The binding activity of AP°C3 and PCYOX1 was shown in Figure 1, and this effect was in a dose dependent manner.