Nano-ESI-MS/MS identification on differentiation-associated proteins in M1 mouse myeloid leukemia cells induced by IL-6

Objective: To identify two differentiation-associated proteins induced by rhIL-6 in M1 mouse myeloid leukemia cells.

Methods: Protein spots were excised from 2-D gels and digested in-gel with trypsin. The trypsin lysis products were first analyzed by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) through peptide mass fingerprinting and then performed peptide sequencing by nano-electrospray ionization mass spectrometry/mass spectrometry (nano-ESI-MS/MS). The database search was finished with the Mascot search engine (http://www.matrixscience.co.uk) using the data processed through MaxEnt3 and MasSeq.

Results: The two proteins were not revealed by peptide mass fingerprint using MALDI-TOF-MS, while they were respectively identified as Destrin and Putative protein after the sequence of their trypic peptides were obtained by the nano-ESI-MS/MS techniques.

Conclusions: Nano-ESI-MS/MS technique can successfully identify the two differentiation-associated proteins induced by rhIL-6 and has great advantage in protein analysis.