Post-Translational Processing of Cholecystokinin in Pig Brain and Gut

A sequential extraction method employing methanol extraction of the COOH-terminal fragments of cholecystokinin (CCK) from pig tissues followed by HCl extraction of intact CCK and its NH2-terminal fragments is described. Radioimmunoassay of extracts and their fractionation by Sephadex chromatography...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 1982-10, Vol.79 (19), p.6060-6064
Main Authors: Eng, John, Shina, Yoshiharu, Straus, Eugene, Yalow, Rosalyn S.
Format: Article
Language:English
Subjects:
Animals
Antiserum
Brain
Brain - metabolism
Cholecystokinin - genetics
Cholecystokinin - isolation & purification
Chromatography, High Pressure Liquid - methods
Elution
Extraction
Fractionation
Gels
Hospital administration
Intestinal Mucosa - metabolism
Intestine, Small - metabolism
Medical sciences
Molecules
Mucosa
Organ Specificity
Protein Processing, Post-Translational
Swine
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Description
Summary:A sequential extraction method employing methanol extraction of the COOH-terminal fragments of cholecystokinin (CCK) from pig tissues followed by HCl extraction of intact CCK and its NH2-terminal fragments is described. Radioimmunoassay of extracts and their fractionation by Sephadex chromatography and HPLC demonstrate that the distributions of COOH-terminal and NH2-terminal immunoreactivities among various regions of brain are similar and independent of the concentrations in individual regions. The distribution in gut differs from that in brain. Greatest concentrations of CCK immunoreactivity are located in cortical tissue in the brain and in duodenal mucosa in gut. Both brain and gut contain CCK octapeptide (CCK8) and an NH2-terminal fragment that is likely to be desoctapeptide-CCK33. Intact CCK33 is extractable from gut but not from brain. Brain contains another NH2-terminal immunoreactive molecule lacking COOH-terminal immunoreactivity that may be a peptide with a COOH-terminal extension, as has been described for gastrin, or one that may not be derived from a CCK33-like precursor. This peptide is much less prominent in gut, or may be nonexistent there. The failure to find CCK33 in the brain and the presence in the brain of this as-yet-uncharacterized NH2-terminal peptide raises the question as to whether the differences between neuronal and mucosal tissues are a consequence of differences in post-translational processing or in the DNA templates.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.79.19.6060