Arylsulfatase B (ARSB) is a lysosomal enzyme of the sulfatase family. ARSB hydrolyzes sulfate groups of N-Acetyl-D-galactosamine, chondriotin sulfate, and dermatan sulfate. The protein is targetted to the lysozyme. Besides, Plasminogen Activator, Urokinase Receptor (uPAR) has been identified as an interactor of ARSB, thus a binding ELISA assay was conducted to detect the interaction of recombinant human ARSB and recombinant human uPAR. Briefly, ARSB were diluted serially in PBS, with 0.01% BSA (pH 7.4). Duplicate samples of 100uL were then transferred to uPAR-coated microtiter wells and incubated for 2h at 37℃. Wells were washed with PBST and incubated for 1h with anti-ARSB 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℃. Finally, add 50µL stop solution to the wells and read at 450nm immediately. The binding activity of of ARSB and uPAR was shown in Figure 1, and this effect was in a dose dependent manner.