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Description
C-terminal aromatic amino acids — phenylalanine, tyrosine or tryptophan — can block protein sequencing, complicate peptide map interpretation, and obscure the true C-terminus of a peptide or protein. Removing or identifying these C-terminal residues cleanly and reproducibly with a well-characterized exopeptidase is a routine first step in protein analysis.
Carboxypeptidase A from bovine pancreas (EC 3.4.17.1) is a zinc-containing pancreatic exopeptidase that preferentially hydrolyzes peptide bonds at C-terminal aromatic amino acids — phenylalanine, tyrosine and tryptophan:
Peptidyl-L-phenylalanine + H2O → Peptide + L-Phenylalanine
Also known as peptidyl-L-amino acid hydrolase, this Carboxypeptidase A has a molecular weight of approximately 35,000 Da and an optimal pH range of 7-8. Glycine, aspartic acid and glutamic acid are hydrolyzed slowly, while arginine, proline and hydroxyproline are not hydrolyzed.
The enzyme activity is precisely defined: one unit hydrolyzes 1 µmol of hippuryl-L-phenylalanine per minute at 25°C and pH 7.5, and hydrolysis is followed directly by the increase in absorbance at 254 nm. For the assay, the enzyme is dissolved in 10% LiCl at 1-3 U/ml and added to a 1 mM hippuryl-L-phenylalanine solution in 50 mM Tris/HCl buffer (containing 1.0 M NaCl), pH 7.5. With this clear unit definition and simple spectrophotometric assay, Carboxypeptidase A delivers reproducible C-terminal digestion for protein analysis workflows.
Specification
| Product Name | Carboxypeptidase A |
|---|---|
| Synonyms | Peptidyl-L-amino acid hydrolase |
| Catalog Number | BF-2060050 |
| EC Number | 3.4.17.1 |
| Biological Source | Bovine pancreas |
| Molecular Weight | Approximately 35,000 Da |
| Optimal pH | 7-8 |
| Unit Definition | One unit hydrolyzes 1 µmol hippuryl-L-phenylalanine per minute at 25°C, pH 7.5 |
| Assay Method | Increase in absorbance at 254 nm during hydrolysis of hippuryl-L-phenylalanine |
Features
- Preferential hydrolysis of C-terminal aromatic amino acids — phenylalanine, tyrosine and tryptophan
- Zinc-containing metalloexopeptidase from bovine pancreas with a molecular weight of approximately 35,000 Da
- Zinc ion tightly coordinated by two histidine imidazole rings and the carboxyl group of one glutamic acid residue
- Optimal pH range of 7-8
- Slow hydrolysis of glycine, aspartic acid and glutamic acid; no hydrolysis of arginine, proline or hydroxyproline
- Well-defined unit: 1 U hydrolyzes 1 µmol hippuryl-L-phenylalanine per minute at 25°C, pH 7.5
- Simple spectrophotometric activity monitoring at 254 nm
- Assay-ready: dissolved in 10% LiCl to 1-3 U/ml for the activity assay
Application
Carboxypeptidase A is used in protein analysis workflows:
- Protein C-terminal amino acid determination and sequencing
- Removal of C-terminal aromatic amino acids (phenylalanine, tyrosine, tryptophan) from peptides and proteins
- Peptide mapping and proteomics sample preparation
- Characterization of C-terminal residues of peptides and proteins
FAQ
What is Carboxypeptidase A?
Carboxypeptidase A (EC 3.4.17.1), also known as peptidyl-L-amino acid hydrolase, is a zinc-containing pancreatic exopeptidase from bovine pancreas with a molecular weight of approximately 35,000 Da. It preferentially hydrolyzes peptide bonds at C-terminal aromatic amino acids.
What is the source of this Carboxypeptidase A?
This Carboxypeptidase A is derived from bovine pancreas.
Which amino acids does Carboxypeptidase A cleave?
Carboxypeptidase A preferentially hydrolyzes C-terminal aromatic amino acids — phenylalanine, tyrosine and tryptophan. Glycine, aspartic acid and glutamic acid are hydrolyzed slowly, while arginine, proline and hydroxyproline are not hydrolyzed.
What is the optimal pH of Carboxypeptidase A?
The optimal pH range of Carboxypeptidase A is 7-8.
How is Carboxypeptidase A activity defined?
One unit of Carboxypeptidase A hydrolyzes 1 µmol of hippuryl-L-phenylalanine per minute at 25°C and pH 7.5.
How is Carboxypeptidase A activity measured?
Activity is measured by the increase in absorbance at 254 nm during hydrolysis of hippuryl-L-phenylalanine. The initial linear rate (ΔE254/min) is used in the formula: Activity (U/mg) = (ΔE254/min × Total Vol. × Enz. Diln.) / (0.36 × mg Enz./ml).
Is Carboxypeptidase A a metalloenzyme?
Yes. Carboxypeptidase A is a zinc-containing metalloenzyme; the zinc ion is tightly coordinated by two histidine imidazole rings and the carboxyl group of one glutamic acid residue.
How should the enzyme be prepared for the activity assay?
Dissolve Carboxypeptidase A in 10% LiCl to 1-3 U/ml, and add to a 1 mM hippuryl-L-phenylalanine solution in 50 mM Tris/HCl buffer (containing 1.0 M NaCl), pH 7.5. Monitor the increase in absorbance at 254 nm over 5 minutes at 25°C, using the initial linear rate for calculation.
For research use only. Not for use in diagnostic or therapeutic procedures.
