SILAC labelling is a powerful, versatile tool relying on metabolic sample labelling with non-radioactive isotopically labelled amino-acids. Up to 3 different samples can be analysed simultaneously as one combined sample.
SILAC = “Stable Isotopic Labelling of Amino acids
in Cell culture”.
Cells are grown in medium containing arginine (R) and lysine
(K) that contain heavier, stable isotopes, i.e. additional neutrons. Labelled amino acids are metabolically incorporated into new proteins.
SILAC can be double (Light vs. Heavy) or triple (Light vs.
Medium vs. Heavy).
Since trypsin cleaves after R and K, only these amino acids
are typically labelled, ensuring all peptides except the C-terminal one are labelled.
Typical SILAC labels
– medium Arginine = “R6” -> +6 Da
– medium Lysine = “K4” -> +4 Da
– heavy Arginine = “R10” -> +10 Da
– heavy Arginine = “K8” -> +8 Da