What is the ratio and composition of Trypsin and Lys-C in Trypsin/Lys-C Protease Mix, MS Grade (Cat. No. A41007)?
Trypsin and Lys-C are present in a 1:1 ratio in Trypsin/Lys-C Protease Mix, MS Grade (Cat. No. A41007). The mix contains 10 µg of each protease.
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What is the best enzyme to use for protein digestion for mass spectrometry samples?
Trypsin (Cat. Nos. 90057, 90058) or Trypsin/LysC mix (Cat. Nos. A40007, A40009, A41007) are most commonly used for proteomic applications in order to ensure reproducibility and complete digestion. Other commonly used enzymes for purified protein characterization and unique applications include Chymotrypsin Protease, MS Grade (Cat. No. 90056), Immobilized Pepsin (Cat. No. 20343), LysN Protease, MS Grade (Cat. No. 90300), Asp-N Protease, MS Grade (Cat. No. 90053), and Glu-C Protease, MS Grade (Cat. No. 90054).
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Is the trypsin in Pierce Trypsin/Lys-C Protease Mix, MS-Grade modified?
Yes, the MS-Grade trypsin protease in this mix is derived from porcine pancreatic extracts and has been Tosyl phenylalanyl chloromethyl ketone (TPCK)-treated to eliminate chymotryptic activity, and methylated to improve stability during digestion.
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Why are trypsin and Lys-C used together in the Pierce Trypsin/Lys-C Protease Mix, MS-Grade?
Trypsin cuts at the carboxyl end of lysine and arginine residues, and Lys-C protease cuts at the carboxyl end of just lysine residues with Lys-C being more efficient than trypsin. Although trypsin is routinely used for protein digestion, this protease alone is not sufficient to fully digest proteins at the carboxyl-end of lysine and arginine residues. Therefore, Lys-C is combined with trypsin to sequentially digest proteins with fewer missed cleavage points at lysines.
The added benefit of having trypsin and Lys-C together is that unlike trypsin, Lys-C can cleave lysines followed by prolines.
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