Assay methods may generally comprise forming homogeneous assay mixtures comprising target SAM-utilizing protein, fluorescent detection analyte, and test compound, incubating, and measuring FP or TR-FRET signal emitted in order to determine a measure of test compound-SAM -utilizing protein binding. Assay mixtures comprise a SAM-utilizing protein, and a fluorescent detection analyte that binds with the SAM-utilizing protein in the absence of test compound. Assay mixtures may further comprise a test compound. Assay mixture embodiments may generate FP or TR-FRET signal properties that are a function of the inherent binding interactions of both the test compound and the detection analyte with the SAM-utilizing protein. Fluorescent detection analytes comprise a fluorophore moiety, a covalent linker moiety, and a SAM-utilizing protein ligand moiety and could be utilized in FP or TR-FRET assays to measure test compound binding.