L-Lysine ¹³C₆ hydrochloride, 100 mg, glass

Our amino acids are of the highest purity and suitable for a broad range of applications in biochemistry. Besides the natural occurring L-amino acids, we offer a selection of unnatural D-amino acids and DL-amino acids.

Stable Isotope Labelling with Amino Acids in Cell Culture (SILAC) is a metabolic labelling technique for mass spectrometric (MS)-based quantitative proteomics. For this purpose originally identical cell cultures are cultivated with different nutrient media. One of the cell populations is fed with growth medium containing unlabelled amino acids. In contrast, the second cell culture is fed with a medium containing one or two amino acids labelled with stable (non-radioactive) heavy isotopes. For example, the medium may contain arginine labelled with ¹³C carbon instead of the normal ¹²C carbon. The cells growing in this medium incorporate the heavy arginine into all their proteins. Then all peptides containing a single arginine are 6 Dalton heavier than their normal counterparts. The proteins from both cell populations are then mixed together in a ratio of 1:1 and analysed by mass spectroscopy. Pairs of chemically identical peptides of different isotopic compositions can be distinguished in a mass spectrometer on the basis of their mass difference. The ratio of the intensities in the mass spectrum for such peptide pairs reflects the frequency ratio for the two proteins.

References:
S.-E. Ong and M. Mann, A practical recipe for stable isotope labeling by amino acids in cell culture (SILAC). Nature Protocols 2006, 1, 2650-2660.