Methods for detecting transferase activity of a sample are provided. Transferase activity detected includes kinase and phosphatase activity. The method includes providing a substrate having a reporter compound conjugated thereto. A quantity of the substrate is added to a solution containing the sample. The sample is incubated with the substrate under conditions where the sample is active for a time sufficient for kinase or phosphatase activity to take place. An exopeptidase is added to the solution containing the sample. Output of the reporter compound is detected.