Tubulin is the major constituent of microtubules, a cylinder consisting of laterally associated linear protofilaments composed of alpha- and beta-tubulin heterodimers. Tubulin Beta (TUBb) is a spherical molecule which is composed of 455 amino acids. Tyrosine 3/Tryptophan 5 Monooxygenase Activation Protein Zeta (YWHAz) has a remarkably high affinity for TUBb, thus a functional binding ELISA assay was conducted to detect the interaction of recombinant human TUBb and recombinant human YWHAz. Briefly, TUBb was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to YWHAz-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-TUBb 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 450/630 nm immediately. The binding activity of recombinant human TUBb and recombinant human YWHAz was shown in Figure 1, the EC50 for this effect is 0.88 ug/mL.