▎ 摘　　要

Protein p300 is a transcriptional co-activator that participates in many physiological processes including cell cycle control, differentiation and apoptosis. It serves (a) as a protein bridge that links specific transcription factors to the fundamental transcription machinery, (b) as a scaffold to complete multiple transcription cofactors, and (c) as an enzyme for acetylating histone and non-histone proteins. An ultrasensitive electrochemiluminescence (ECL) immunosensor is described herethat is based on the use of a magnetic glassy carbon electrode modified with tetrahedral DNA with hollow structure, graphene oxide (GO) and gold nanocrystals. The use of a GO monolayer allows for greater carrying capacity and warrants a wider outer Helmholtz plane. Strong and stable ECL signals were achieved due to antigen-antibody interaction by using the ECL probe Ru(phen)(3)(2+). This immunosensor has a response that covers the 0.005 to 80nM p300 concentration range and has a 1 pM detection limit. It was exploited for the determination of p300 in HeLa cell lysate and (spiked) serum.