title: The activation segment of procarboxypeptidase A from porcine pancreas constitutes a folded structural domain.
abstract: The controlled action of trypsin on porcine pancreatic procarboxypeptidase A releases a large activation peptide which contains the activation segment of the proenzyme. Circular dichroism studies indicate that the isolated activation peptide contains a high percentage of residues in ordered secondary structures (mainly alpha-helix). This result agrees with predictions of secondary structure carried out on the published amino acid sequence of the homologous rat proenzyme. Moreover, proton magnetic resonance spectroscopy shows that the peptide adopts a thermostable tertiary structure with characteristics typical of globular proteins. The results as a whole indicate that the activation segment of porcine pancreatic procarboxypeptidase A constitutes a folded structural domain.
mesh_terms: D000818:Animals; D001665:Binding Sites; D002268:Carboxypeptidases / Q000032:analysis*; D043422:Carboxypeptidases A; D002942:Circular Dichroism; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D010179:Pancreas / Q000201:enzymology*; D011487:Protein Conformation; D013552:Swine; D014357:Trypsin / Q000378:metabolism
chemical_list: D004792:Enzyme Precursors; D002268:Carboxypeptidases; D043422:Carboxypeptidases A; D014357:Trypsin