TY - JOUR
T1 - A processing enzyme cleaving avian progastrin at post-Phe bonds
AU - Jensen, H
AU - Ørskov, C
AU - Rehfeld, J F
AU - Johnsen, A H
PY - 2001/5/5
Y1 - 2001/5/5
N2 - Neuroendocrine peptides mature partly through endoproteolytic processing of long precursor forms. Best characterised is cleavage at mono- and dibasic residues, but additional sites also exist. Among these is post-Phe cleavage, first suggested to participate in the processing of chicken progastrin. In order to characterise this new mechanism, antibodies recognising the processing products of post-Phe cleavage of chicken progastrin were produced for radioimmunoassay measurements and immunocytochemistry. High concentrations of the carboxyamidated C-terminus and the N-terminus of gastrin-53 were measured in extracts of the antrum. In addition, significant amounts were detected using an assay specific for the N-terminus of gastrin-30 and with another assay for the C-terminus of the corresponding peptide, gastrin-53(1-23), obtained after cleavage at the Phe(23)-Ala(24) bond of gastrin-53. Colocalisation in antral G-cells of the N-termini of gastrin-53 and gastrin-30 and of the C-terminus of gastrin-53(1-23) was confirmed by immunohistochemistry. Finally, we identified the intact N-terminal 1-23 fragment of gastrin-53 complementary to gastrin-30, verifying endoproteolytic cleavage at the Phe(23)-Ala(24) bond. Taken together, the results support the existence of vertebrate endoprotease cleaving hormone precursors at post-Phe sites.
AB - Neuroendocrine peptides mature partly through endoproteolytic processing of long precursor forms. Best characterised is cleavage at mono- and dibasic residues, but additional sites also exist. Among these is post-Phe cleavage, first suggested to participate in the processing of chicken progastrin. In order to characterise this new mechanism, antibodies recognising the processing products of post-Phe cleavage of chicken progastrin were produced for radioimmunoassay measurements and immunocytochemistry. High concentrations of the carboxyamidated C-terminus and the N-terminus of gastrin-53 were measured in extracts of the antrum. In addition, significant amounts were detected using an assay specific for the N-terminus of gastrin-30 and with another assay for the C-terminus of the corresponding peptide, gastrin-53(1-23), obtained after cleavage at the Phe(23)-Ala(24) bond of gastrin-53. Colocalisation in antral G-cells of the N-termini of gastrin-53 and gastrin-30 and of the C-terminus of gastrin-53(1-23) was confirmed by immunohistochemistry. Finally, we identified the intact N-terminal 1-23 fragment of gastrin-53 complementary to gastrin-30, verifying endoproteolytic cleavage at the Phe(23)-Ala(24) bond. Taken together, the results support the existence of vertebrate endoprotease cleaving hormone precursors at post-Phe sites.
KW - Amino Acid Sequence
KW - Animals
KW - Antibodies/immunology
KW - Binding Sites
KW - Chickens
KW - Chromatography, Gel
KW - Digestive System/metabolism
KW - Epitopes/immunology
KW - Fluorescent Antibody Technique
KW - Gastric Mucosa/metabolism
KW - Gastrins/chemistry
KW - Molecular Sequence Data
KW - Peptides/chemical synthesis
KW - Protein Precursors/chemistry
KW - Pyloric Antrum/metabolism
KW - Radioimmunoassay
KW - Tissue Extracts/chemistry
M3 - Journal article
C2 - 11343792
SN - 0006-3002
VL - 1547
SP - 64
EP - 71
JO - B B A - Reviews on Cancer
JF - B B A - Reviews on Cancer
IS - 1
ER -