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Proglucagon processing in porcine and human pancreas
J J Holst1, M Bersani, A H Johnsen
1Department of Medical Physiology, Panum Institute, Copenhagen, Denmark.
The Journal of Biological Chemistry
|July 22, 1994
Summary
Researchers identified key fragments of proglucagon processing in the pancreas. The C-terminal flanking peptide yields glucagon-like peptide-1 (GLP-1) and a major fragment, PG 72-158.
Area of Science:
- Endocrinology
- Molecular Biology
- Biochemistry
Background:
- Proglucagon (PG) processing in the pancreas yields glucagon and N-terminal peptides.
- The fate of the C-terminal flanking peptide of proglucagon remains incompletely understood.
Purpose of the Study:
- To elucidate the processing of the C-terminal flanking peptide of human and porcine proglucagon.
- To identify and characterize the peptides generated from this region.
Main Methods:
- Gel filtration and high-performance liquid chromatography (HPLC) of pancreatic extracts.
- Radioimmunoassays targeting specific proglucagon regions.
- Mass spectrometry and N-terminal sequencing for peptide identification.
Main Results:
- Isolated and purified three porcine peptides: PG 64-69, PG 72-108, and a ~10,000 Da peptide (PG 72-158).
- Identified a similar ~9969 Da peptide (PG 72-158) in human pancreas, along with PG 72-107 amide.
- Demonstrated equimolar formation of PG 64-69 and PG 72-158, with smaller amounts of GLP-1 variants.
Conclusions:
- Pancreatic processing of the C-terminal proglucagon peptide generates PG 64-69 and the major proglucagon fragment (PG 72-158) in equimolar amounts to glucagon.
- Smaller quantities of N-terminally extended glucagon-like peptide-1 (GLP-1) are also produced.