Sigma-Aldrich α-Chymotrypsin from bovine pancreas, TLCK treated, Type VII

Sigma-Aldrich α-Chymotrypsin (Type VII) is a serine endopeptidase prepared from bovine pancreas. It is supplied as an essentially salt-free, lyophilized powder and treated with TLCK (Nα-p-tosyl-L-lysine chloromethyl ketone) to inactivate any residual trypsin activity without affecting chymotrypsin function. With a specific activity ≥40 units/mg protein, it is a highly pure and reliable enzyme preparation for structural biology, proteomics, and biochemical assays.

Key Features

• Source: Bovine pancreas, Type VII.
• Form: Lyophilized powder, essentially salt-free.
• Specific activity: ≥40 units/mg protein.
• Molecular weight: ~25 kDa.
• Solubility: Soluble in 1 mM HCl at 10 mg/mL (clear solution).
• Stability: Activated and stabilized by Ca²⁺.
• Inhibitors: DFP, PMSF, TPCK, chymostatin, aprotinin, α1-antitrypsin, α2-macroglobulin, Cu²⁺, Hg²⁺.
• Storage: –20 °C (long-term stability).
• UniProt Accession: P00767.

Biochemical/Physiological Actions

• A serine protease with 241 amino acid residues arranged in three disulfide-linked chains (A, B, C).
• Isoelectric point (pI): 8.75.
• Selectively hydrolyzes peptide bonds at the C-terminal of aromatic and hydrophobic residues: tyrosine, tryptophan, phenylalanine, methionine, and leucine.
• Commonly used in protein digestion and peptide mapping due to its well-defined cleavage specificity.
• Plays a significant role in studying enzyme inhibition, protein structure, and stability.

Applications

• Structural biology & crystallography: Determination of protein-inhibitor complex structures.
• Proteomics: Controlled digestion of proteins for peptide mapping and sequence analysis.
• Biochemical research: Substrate specificity and enzyme kinetics studies.
• Pharmaceutical research: Screening of protease inhibitors and drug design.
• Education & training labs: Demonstrating serine protease activity and inhibition.

Specifications

The Sigma-Aldrich α-Chymotrypsin from Bovine Pancreas, Type VII is a high-purity serine protease preparation optimized for structural biology, proteomics, and enzymology research. With TLCK treatment to remove contaminating trypsin, this enzyme ensures high specificity and reproducibility. Its defined cleavage preferences make it indispensable for protein sequencing, inhibitor studies, and drug discovery applications.