The IMAP FP Substrate Finder enables the researcher to quickly test one or more kinases against dozens of peptides included in a 384-well microtiter plate to identify potential substrates for subsequent IMAP screens. This new assay development tool significantly limits the time spent searching for a suitable substrate. Additionally, substrate specificity may be evaluated between different kinase variants or among different mutants of the same kinase. The Substrate Finder also allows the researcher to screen through dozens of predefined potential substrates for less than the cost of a few unknown potential substrates. Once a substrate is identified, it can be used with IMAP in either FP or TR-FRET detection mode. Depending on the mode chosen, optimized conditions may vary.