Human pancreatic proelastase 2. Sequence of the activation peptide

Area of Science:

• Biochemistry
• Enzymology
• Proteomics

Background:

• Human pancreatic proelastase 2 is a precursor to the enzyme elastase.
• Understanding its structure and activation is crucial for digestive physiology.
• Previous studies have characterized related enzymes like chymotrypsinogens.

Purpose of the Study:

• To determine the N-terminal amino acid sequence of human pancreatic proelastase 2.
• To investigate the structure of the activation peptide released during proelastase 2 activation.
• To compare the activation peptide sequence with homologous proteins.

Main Methods:

• Reduced and alkylated human pancreatic proelastase 2.
• Peptide isolation using trypsin activation, performic acid oxidation, and gel filtration.
• Amino acid sequencing.

Main Results:

• The N-terminal sixteen residues of human pancreatic proelastase 2 were established.
• The N-terminal residue was identified as carboxymethylcysteine.
• A twelve-residue activation peptide was isolated, suggesting disulfide bond linkage.
• The activation peptide showed limited homology to porcine chymotrypsinogen A and proelastase 1.

Conclusions:

• The N-terminal region of human pancreatic proelastase 2 has a carboxymethylcysteine residue.
• The activation peptide is likely held by a disulfide bond, similar to chymotrypsinogens.
• Human proelastase 2 activation peptide sequence is distinct from porcine homologs.