ten-eleven translocation (tet) dioxygenase is of great significance in cytosine demethylation and in the control of cell differentiation and transformation. herein, a fluorescence method has been developed for the highly sensitive detection of tet1, a member of the tet dioxygenase family. based on the tht-induced specific conformation of the g-quadruplex structure, the fluorescence signal decreased linearly with increasing tet1 concentration. the method shows potential clinical applications in the screening of tet protein inhibitors for anticancer drug discovery.