This first-attempt study provided liquid chromatography tandem mass (LC-MS/MS) proteomics approach to explore precursor effects on daptomycin synthesis from Streptomyces roseosporus NRRL 11379. Among all, 357 and 691 differential proteins from 601 proteins in precursor group (144 h+) and 935 proteins in non-precursor group (144 h-) were identified, respectively. Through the simulation of the 2D-protein mapping, most proteins were found in isoelectric points ranged of 4.5-10.0 as well as Mws ranged 10-100 kDa. As a result, LC-MS/MS analysis was consistence with the analytical results of two-dimensional electrophoresis (2DE) but provided much intact profiles of proteins by precursor effect on S. roseosporus. To have more insight exploration, differential proteins associated to Streptomyces spp. were defined into 14 groups of their functional classification. The major differential proteins were in transport/membrane functional group with an occupation of 12.4% for 144 h+ and 5.2% for 144 h-, respectively. LC-MS/MS results as a direct proteomic mapping approach reveal more daptomycin synthetic and regulation-related proteins from precursor group in terms of methyltransferase, ATP-binding cassette (ABC) transporters, resistance proteins and regulators. (C) 2013, The Society for Biotechnology, Japan. All rights reserved.