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J Vendrell

Publications and source records attributed to J Vendrell.

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Conformational predictive studies on the activation segment of pancreatic procarboxypeptidases.

Little is known about the conformation and evolutionary origin of the activation segment of pancreatic procarboxypeptidases. Analysis of the sequence and secondary structure propensities of these propeptide segments indicate that they contain two regions structurally related to the Ca2+-binding sites of the EF-hand protein family. This proposed homology could explain how (and why) carboxypeptidases developed such long (94 residues) activation peptides.

Animals

Primary structure of the activation segment of procarboxypeptidase A from porcine pancreas.

The complete primary structure of the activation segment of monomeric procarboxypeptidase A from porcine pancreas has been determined by automated and manual Edman-like degradation methods performed on its fragments generated by enzymatic cleavage. The polypeptide consists of 94 residues, with a molecular mass of 10,768, and presents a high proportion of acidic and hydrophobic residues and a proline-rich region in the center of the molecule. Comparison of this sequence with the already reported equivalent sequence deduced from rat procarboxypeptidase A cDNA reveals a very high degree of homology between the two propeptides (up to a 81% of identities), which is even higher in certain large zones of the molecule.

Amino Acid Sequence

Preparative isolation of the two forms of pig pancreatic pro-(carboxypeptidase A) and their monomeric carboxypeptidases A.

A method is reported for the preparative isolation of the two forms of pro-(carboxypeptidase A) from pig pancreas: the monomer and the binary complex with pro-(proteinase E). This method, which is mainly based on chromatography on DEAE-Sepharose at pH 5.7, allows these proenzymes to be prepared more quickly and in safer conditions than with other reported methods. Undegraded and homogeneous carboxypeptidase A1 and A2 species (peptidyl-L-amino acid hydrolase, EC 3.4.17.1), in monomeric forms with high specific activity, are also obtained in high yield by controlled trypsin activation of either of the pro-(carboxypeptidases A) followed by chromatography on DEAE-Sepharose at pH 5.8 under dissociating conditions (7 M-urea).

Animals

Sequential homologies between procarboxypeptidases A and B from porcine pancreas.

Automated Edman degradation of monomeric procarboxypeptidases A and B from porcine pancreas shows that their N-terminal regions (from residue 1 to 34-37) present a high degree of sequential homology to each other as well as to other related procarboxypeptidases. Conformational predictions based on these sequences confirm their structural homology and indicate the probable existence of two beta-turns, one beta-chain and a long alpha-helix in them. On the other hand, tryptic peptide maps on a reverse-phase column indicate great sequential similarities (if not identity) between monomeric procarboxypeptidase A and the procarboxypeptidase A subunit isolated from its binary complex with proproteinase E.

Amino Acid Sequence

Isolation and re-association of the subunits from the pro-(carboxypeptidase A)-pro-(proteinase E) binary complex from pgi pancreas.

The component subunits of the pro-(carboxypeptidase A)-pro-(proteinase E) binary complex from pig pancreas were separated with a high recovery (80-95%) of their original potential activity. The isolated subunits and the reconstituted complex have properties similar to those of the corresponding natural species. The tryptic activation course of the pro-(carboxypeptidase A) subunit is substantially modified when bound to pro-(proteinase E), whereas the activation of pro-(proteinase E) is not dependent on this association.

Animals