Identification of four chicken gastrins, obtained by processing at post-Phe bonds.
Chicken antrum was found to contain 7 nmol/g of carboxyamidated gastrin/CCK-like peptides. The predominant chicken gastrin (so named due to the antral origin) contained 53 amino acid residues: DWPEPPSQEQ QQRFISRFLP HVFAELSDRK GFVQGNGAVE ALHDHFYPDW MDF-NH2. Three smaller (less abundant) forms corresponded to the 30-, 21-, and 7-residue carboxyamidated C-terminal fragments. The major part was sulfated at the tyrosine residue in position seven from the C-terminus. A lower isoelectric point and abrupt termination of the sequencing suggest that some of the peptides had an isoAsp-Gly bond instead of an Asn-Gly bond. The three shorter forms were all derived from the precursor by post-Phe cleavages. This cleavage pattern suggests a processing enzyme specific for bonds between Phe and moderately hydrophobic residues.
Bjørnskov
I
I
Department of Clinical Biochemistry, University Hospital, Copenhagen, Denmark.
Rehfeld
J F
JF
Johnsen
A H
AH
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002645:Chickens / Q000502:physiology*; D003429:Cross Reactions; D005753:Gastric Mucosa / Q000737:chemistry*; D005755:Gastrins / Q000737:chemistry* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D011499:Protein Processing, Post-Translational; D011706:Pyloric Antrum / Q000737:chemistry*; D011863:Radioimmunoassay
D000596:Amino Acids; D005755:Gastrins