Analysis of the activation process of porcine procarboxypeptidase B and determination of the sequence of its activation segment
| Autor: | Virtudes Villegas, Fernando Soriano, Enrique Méndez, Francesc X. Avilés, Miquel Salva, Francisco J. Burgos |
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| Rok vydání: | 1991 |
| Předmět: |
Protein Conformation
Swine Molecular Sequence Data Carboxypeptidases Cleavage (embryo) Biochemistry Protein structure Zymogen medicine Animals Trypsin Amino Acid Sequence Peptide sequence chemistry.chemical_classification Enzyme Precursors Edman degradation biology Chemistry Carboxypeptidase Carboxypeptidase B Peptide Fragments Enzyme Activation Molecular Weight Kinetics Enzyme biology.protein Protein Processing Post-Translational Mathematics Protein Binding medicine.drug |
| Zdroj: | Scopus-Elsevier |
| ISSN: | 1520-4995 0006-2960 |
| DOI: | 10.1021/bi00230a038 |
| Popis: | The molecular events which lead to the proteolytic transformation of porcine procarboxypeptidase B (PCPB) in carboxypeptidase B (CPB) have been determined. Among pancreatic and other tested proteinases, trypsin is the only one capable of generating carboxypeptidase B activity from the zymogen, in vitro. In the first step of this process, trypsin produces cleavage at the boundary between the activation region and the CPB region. Subsequently, a definite sequence of cleavages occurs at the C-terminal end of the released activation segment of 95 residues, giving rise to characteristic intermediates and to a proteolytically resistant activation fragment of 81 residues. In this process, the newly formed CPB participates in the quick-trimming of the released activation peptides. Only a single CPB species is formed in the activation process. This fact and the inability of the released activation peptides to inhibit CPB--and, therefore, their inability to slow down the kinetics of appearance of CPB activity--are two important characteristics differentiating between the activation processes of procarboxypeptidases A and B. The sequence of the 95 residues (MW = 12,835) of the activation region of porcine PCPB has also been deduced, largely from the information obtained by Edman degradation of its fragments and in part by considerations of homology with the rat precursor. The porcine PCPB activation region contains a high percentage of acidic residues, lacks cysteines, methionines, and side-chain posttranslational modifications, and presents a low but significant homology (31%) with the corresponding sequence of porcine procarboxypeptidase A. |
| Databáze: | OpenAIRE |
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