Updated project metadata. Peltate glandular trichomes from /Mentha spicata /were purified on a Percoll gradient and soluble and membrane proteins were trypsinized and the peptides separated by nano-LC fractionation and analyzed by MALDI-MS/MS. The vast majority of the 1,666 proteins identified was housekeeping proteins or involved in primary metabolism. However, 57 were predicted to be involved in secondary metabolism. Of these, 21 were involved in the synthesis of phenylpropanoids and phenolics and 32 in terpenoid synthesis. Of the 14 membrane transporters identified, the 11 ATP-binding cassette transporters provide good material for assessing whether active transport is required for the transfer of monoterpenoid intermediates between cellular compartments and for the secretion of the final products into the subcuticular storage cavity. In conclusion, this proteome analysis of /M. spicata/ peltate trichomes has identified several candidate proteins that might be involved in terpenoid synthesis and transport. MALDI-MS/MS analyses were performed as described previously (Szopinska et al., 2011). MS data from the soluble and microsomal fractions were pooled and analyzed as a single data set using ProteinPilotTM software (AB SCIEX, v.4.0.8085). Protein identification was based on ParagonTM algorithm v.4.0 and used the Viridiplantae part of the whole NCBInr protein database (downloaded on April 14th, 2013). This algorithm in ProteinPilot was used with “identification” as the sample type, “MMTS” as cysteine modification, “4800 TOF/TOF” as the instrument, and the "Thorough" preset search setting. All reported proteins were identified with 95% or greater confidence, as determined by ProteinPilot unused scores (greater than 1.3) using the most stringent threshold of false positive discovery rate, i.e. below 10%. Protein grouping performed by ProteinPilotTM removed redundant hits.