MYC (Myc proto-oncogene protein) is a nuclear phosphoprotein that binds specific sequence of DNA. MYC functions as a transcription factor and regulates transcription of target genes. It has been proven that c-Myc protein is intracellularly associated with TBP (TATA-binding protein) of the TFIID transcription initiation complex; besides, TRRAP (Transformation/transcription domain-associated protein) is thought to be an essential cofactor for the MYC. Thus a binding ELISA assay was conducted to detect the interaction of MYC with TBP and TRRAP. Briefly, recombinant human MYC were diluted serially in PBS, with 0.01%BSA (pH 7.4). Duplicate samples of 100uL were then transferred to TBP-coated and TRRAP microtiter wells and incubated for 2h at 37°C. Wells were washed with PBST and incubated for 1h with anti-MYC 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 MYC with TBP and TRRAP was shown in Figure 1 and Figure 2 separately, and this effect was in a dose dependent manner.