Hebert, A.S. et al. Mol. Cell. Proteomics doi:10.1074/mcp.M113.032011 (23 July 2013).

Hebert, A.S. et al. Nat. Methods 10, 332–334 (2013).

Earlier this year, Nature Methods published a paper describing a neutron-encoding (NeuCode) stable-isotope labeling by amino acids in cell culture (SILAC) method that extended the number of possible quantitative proteomics comparisons by SILAC from a standard 3 to up to a theoretical 39 (Hebert et al., Nat. Methods). In this approach, different combinations of stable-isotope labels are encoded into an amino acid and decoded by high-resolution mass spectrometry; the method exploits subtle mass differences in atoms due to varying nuclear binding energies. Practically speaking, however, the approach is limited to a handful of comparisons because of limited reagent availability. Hebert et al. (Mol. Cell. Proteomics) now report the design and synthesis of additional NeuCode reagents to allow practical 12-plex quantitative proteome comparisons.