MRMaid helps you design SRM assays by suggesting peptides and product ions to monitor based on millions of experimental spectra from the public data repository known as PRIDE database (PRoteomics IDEntifications; www.ebi. ac.uk/pride). This Web-based application developed suggests SRM transitions based on the peptides and fragment ions that have been detected previously in shotgun proteomics experiments stored in PRIDE.MRMaid also provides information that can aid in the design of a targeted assay, such as the peptide’s retention time, the m/z values for the peptide and fragment ion, and the average intensity of the ion (Cham et al., J Proteome Res. 2010:620). Registration not required.