title: The mechanism of degradation of cyclo(-Asn-Phe-Phe-D-Trp-Lys-Thr-Phe-Gaba-) and the relative stabilities of this and other octapeptide somatostatin analogues in rat intestinal juice.
abstract: The mechanism of degradation of the somatostatin analogue cyclo(-Asn-Phe-4-[3H]-Phe-D-Trp-Lys-Thr-Phe-Gaba-) in rat intestinal juice in vitro has been studied by isolation and identification of cleavage products. The analogue is much more stable than somatostatin but is nevertheless degraded in minutes in dilute intestinal juice. There is a single primary cleavage site at Lys-Thr and the linear peptide thus formed is subsequently rapidly degraded to smaller peptides. Analogues with a modified lysine are markedly stabilised relative to the octapeptide analogue.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D007419:Intestinal Secretions / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000596:Amino Acids; D013004:Somatostatin; C033566:CGP 15425