Naturally occurring products of proglucagon 111-160 in the porcine and human small intestine.
1988; Elsevier BV; Volume: 263; Issue: 18 Linguagem: Inglês
10.1016/s0021-9258(18)68350-4
ISSN1083-351X
AutoresThomas Buhl, L. Thim, Hans Kofod, Cathrine Ørskov, Henrik Harling, Jens J. Holst,
Tópico(s)Glycosylation and Glycoproteins Research
ResumoRecent studies have revealed that the glucagon gene is expressed in the mammalian intestine.Here it codes for "glicentin' (proglucagon 1-69) and a glucagon-like peptide, proglucagon 78-107, recently isolated from porcine intestine.We studied the fate of the remaining COOH-terminal part of proglucagon (proglucagon 11 1-160) using radioimmunoassays against proglucagon 111-123 and 126-160.Two peptides were isolated from acid ethanol extracts of porcine ileal mucosa and sequenced: one corresponding to proglucagon 126-158 and one probably corresponding to proglucagon 111-158.By comparing human and porcine proglucagon sequences, Ala"' is replaced by Thr, and Ile13', Ala14*, Ilele2 and Glnle3 are replaced by Val, Thr, Leu, and His.By gel filtration and radioimmunoassay of intestinal extracts it was established that a large part of porcine and virtually all of human proglucagon are processed to release proglucagon 111-123 (designated spacer peptide 2), which, like proglucagon 126-158 must be considered a potential hormonal entity.By isocratic high pressure liquid chromatography human spacer peptide 2 was indistinguishable from synthetic proglucagon 11 1-122 amide, suggesting that this is the structure of the naturally occurring human peptide.
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