Sigma-Aldrich, α-Chymotrypsin from bovine pancreas

Sigma-Aldrich α-Chymotrypsin is a high-quality Type II serine protease preparation from bovine pancreas, supplied as a lyophilized powder with a specific activity of ≥40 units/mg protein. This enzyme is ideal for diagnostic assay manufacturing, biochemical research, and protein structure-function studies.

This preparation contains ≥85% protein content and exhibits a molecular weight of ~25 kDa. It selectively hydrolyzes peptide bonds at the carboxyl side of aromatic (Tyr, Trp, Phe) and large hydrophobic residues (Met, Leu), making it valuable for proteolytic digestion and enzymatic cleavage protocols.

Key Features and Benefits

• High purity and activity: ≥40 units/mg protein
• Form: Lyophilized powder for enhanced stability and shelf life
• Composition: ≥85% protein
• Molecular weight: ~25 kDa
• Stable at –20 °C for long-term storage
• Derived from 3× crystallized chymotrypsinogen for optimal reproducibility
• Supplied in multiple pack sizes (250 mg, 500 mg, 1 g, 10 g)

Biochemical/Physiological Actions

• Serine protease composed of 241 amino acid residues in three chains (A: 13, B: 131, C: 97) linked by disulfide bonds
• pI: 8.75
• Activated and stabilized by Ca²⁺ ions
• Inhibited by:
  • DFP (diisopropyl fluorophosphate)
  • PMSF (phenylmethanesulfonyl fluoride)
  • TPCK, chymostatin, aprotinin, α₁-antitrypsin, α₂-macroglobulin, 10 mM Cu²⁺ or Hg²⁺

Applications

• Protease digestion in protein and peptide analysis
• Enzymatic cleavage at aromatic/hydrophobic residues
• Protein structure-function studies
• Immobilized metal-ion affinity chromatography (IMAC) and IMACE
• Biological sample processing in diagnostics and research

Unit Definition

One unit hydrolyzes 1.0 μmol of BTEE (N-Benzoyl-L-tyrosine ethyl ester) per minute at pH 7.8, 25 °C.

Preparation & Analysis

• Prepared from 3× crystallized chymotrypsinogen
• Protein content determined by absorbance at 280 nm (E1%/280)

Storage

• Store at –20 °C in a dry environment
• Reconstitute in appropriate buffer immediately before use

Available Pack Sizes

Sigma-Aldrich α-Chymotrypsin Type II is a high-performance protease ideal for targeted enzymatic cleavage in protein research. Its high specificity for aromatic and hydrophobic amino acids, combined with its excellent purity and activity, makes it a trusted reagent in biochemical, diagnostic, and structural biology applications.