Novel ICPL Triplex Protein Quantitation Technology for Expression Proteomics; Three Independent Entire Proteomes can now be Quantified Simultaneously
28 May 2006
At the 2006 ASMS conference, Bruker Daltonics Inc. and Serva Electrophoresis GmbH will announce the release of an ICPL™ triplex kit, based on stable isotope labelling technology which has now been further developed by Drs. Friedrich Lottspeich and Josef Kellermann at the Max Planck Institute of Biochemistry in Martinsried, Germany.
This novel technology enables true quantitative proteomics of three independent proteomes using Isotope Coded Protein Labels (ICPL), resulting in the identification of differentially expressed proteins in triplex analysis with an unmatched dynamic range due to the optional combination with intact protein fractionation steps.
This is possible since, in contrast to other stable isotope labelling approaches, the ICPL labelling step is not limited to the peptide level but is applied already on the protein level. For complex proteomes, the complexity of the resulting peptide mixtures typically exceeds the capacity of 1D or 2D peptide chromatographic steps and requires reduction of complexity. As a unique feature, ICPL allows such reduction of complexity on the protein level by chromatographic or other fractionation steps without any sacrifice of quantitation accuracy.
All lysine side chains are modified selectively and quantitatively by one of the three ICPL tags (L = (12)C(6)(1)H(4), M = (12)C(6)(2)D(4) and H = (13)C(6)(1)H(4)), introducing mass differences of 4Da (M-L) and 6Da (H-L) per labelled site. Thus, multiple peptides from each protein usually carry the ICPL-tags after proteolysis, which allows for robust statistical analysis. The ICPL chemistry also leads to the detection of modified peptides with further increased sensitivity in mass spectrometry.
The ICPL triplex workflow is compatible with all established LC or gel-based protein and peptide fractionation and separation techniques and with all mass spectrometer types on the market, including ion traps. Protein identification and quantitation can be obtained after protein digestion either with ESI-MS/MS on Bruker Daltonics' HCTultra ion trap or micrOTOF-Q Q-q-TOF system, or by using MALDI-MS/MS on the ultraflex II TOF/TOF. For mass spectrometric analysis of ICPL Triplex samples, WARP-LC 1.1 software is now available from Bruker Daltonics to enable multiplexed proteomics quantification. Through a co-marketing agreement between Bruker Daltonics and SERVA, the SERVA ICPL Triplex kit can also be purchased directly from Bruker Daltonics worldwide.
Dr. Detlev Suckau, Head of Proteomics Development at Bruker Daltonik GmbH in Germany, stated: "We consider the new ICPL Triplex labelling technology a breakthrough for true quantitation in proteomics and biomarker discovery. For the first time, three entire proteomes can be analysed quantitatively simultaneously and using robust statistics, cutting down on protein pre-fractionation efforts significantly. The SERVA ICPL triplex kit, in combination with our outstanding LC-ESI and LC-MALDI MS/MS instrumentation, represents a great step forward towards high-fidelity and high-content proteomics. We have used the ICPL kit already very successfully in this year's ABRF 2006 PRG quantification study on our instruments, and we are excited about this new triplex extension of the ICPL kit."
Barbara Mueller, SERVA Electrophoresis GmbH, Heidelberg, said: "SERVA, as a leading supplier of electrophoresis specialty products, is the exclusively licensed distributor of the unique ICPL triplex kit. Under our co-marketing agreement with Bruker Daltonics, new application avenues are opened with clear benefits for proteomics users."
ICPL inventor Professor Friedrich Lottspeich, commented: "Key to the success of proteomics technology is that quantitative information on proteins can be obtained fast and reliably with a high dynamic range in order to access low abundant proteins. These are typically the proteins that matter. That absolutely requires proteome fractionation on the protein level, not only on the peptide level. The ICPL Triplex technology was designed to provide reliable quantitation due to data redundancy and compatibility with any combination of protein fractionation technologies, including one- or two-dimensional gel electrophoresis or protein LC. We are delighted that this powerful technology will now be made available to the scientific community."
