The Thermo Scientific SILAC Protein Quantitation Kit (Trypsin), RPMI 1640, is used for the specific analysis of protein expression by mass spectrometry using stable isotope labeling with amino acids in cell culture (SILAC).

Features of the SILAC Protein Quantitation Kit, RPMI 1640, include:
• Efficient—up to 100% label incorporation into proteins of living cells
• Reproducible—minimizes intra-experimental variability caused by differential sample preparation
• Flexible—media deficient in both L-lysine and L-arginine, allowing for more complete proteome coverage through dual amino acid isotope labeling
• Compatible—label proteins expressed in a wide variety of mammalian cell lines adapted to grow in RPMI 1640 medium, including HeLa, 293T, COS7, U2OS, A549, A431, HepG2, NIH 3T3, Jurkat, and others
• High-quality supplements—heavy amino acids with >99% isotope purity; dialyzed FBS tested to help ensure that it is sterile, endotoxin-free, and cell culture compatible

Applications of SILAC Protein Quantitation Kit:
• Quantitative analysis of relative changes in protein abundance from different cell treatments
• Quantitative analysis of proteins for which there are no antibodies available
• Protein expression profiling to study normal vs disease cells
• Identification and quantification of hundreds to thousands of proteins in a single experiment

SILAC is a powerful method to identify and quantify relative differential changes in complex protein samples. This approach entails the in vivo metabolic incorporation of 'heavy' ¹³C- or ¹⁵N-labeled amino acids into proteins followed by mass spectrometry (MS) for the accelerated and comprehensive identification, characterization, and quantitation of proteins.

Because peptides labeled with heavy and light amino acids are chemically identical, they co-elute during reverse-phase column pre-fractionation and therefore are detected simultaneously during MS analysis. The relative peak intensities of multiple isotopically distinct peptides from each protein are then used to determine the average change in protein abundance in the treated sample.

Trypsin SILAC kits are supplied with ¹³C₆ ¹⁵N₂ L-lysine-2HCl and ¹³C₆ ¹⁵N₄ L-arginine-HCl to label and quantify lysine-containing and arginine-containing peptides from trypsin protein digests. Each kit also includes 2 x 500 mL of medium and dialyzed serum. When combined with Thermo Scientific protein/peptide sample enrichment products, SILAC Protein Quantitation kits also enable MS analysis of low-abundance proteins such as cell surface proteins, organelle-specific proteins, and post-translational protein modifications such as phosphorylation or glycosylation.

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