Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01350 (gastrin)
 9,683 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

COOH-terminal decapeptide of gastrin-releasing peptide (GRP-10) is a bombesin-like peptide, which has bioactivities to stimulate gastrin, insulin, and glucagon secretion. We have synthesized an analogue of GRP-10 that inhibits GRP-10's stimulation of insulin secretion both in vivo and in vitro and glucagon secretion in vivo, while potentiating the stimulation of gastrin secretion. The amino acid sequence of this peptide is H-Gly-Asn-Trp-Ala-Ala-Gly-His-Leu-Met-NH2 ([Ala6]GRP-10). Because the stimulation of insulin and gastrin secretion by GRP-10 has been ascribed to a direct effect on B- and G-cells, these findings suggest that there are two subtypes of receptors for bombesin-like peptides in mammalian tissues.
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PMID:[Ala6]gastrin-releasing peptide-10: an analogue with dissociated biological activities. 266 16

We previously demonstrated that there existed extremely abundant NH2-terminal big gastrin immunoreactivity (NT G-34-IR) in human urine. This report describes the purification and sequence of NT G-34-IR from the urine of an achlorhydric patient. The purification was carried out by a combination of Sep-Pak C18 cartridges, Sephadex G-25, and HPLC steps using a radioimmunoassay specific for NH2-terminus of G-34 and ultraviolet absorption at 214 nm as monitors. Three peptides were isolated. The amino acid analysis, mass spectrometry, and sequence analysis confirmed the structures of urinary NT G-34 fragments being less than Glu-Leu-Gly-Pro-Gln-Gly-Pro-Pro, less than Glu-Leu-Gly-Pro-Gln-Gly- Pro-Pro-His, and less than Glu- Leu-Gly-Pro-Gln-Gly-Pro-Pro-His-Leu. NH2-terminal octapeptide of G-34 was the main component of urinary NT G-34-IR.
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PMID:Purification and structural determination of urinary NH2-terminal big gastrin fragments. 273 Jun 47

Gastrin 17 (G17) is a potent stimulant of gastric acid secretion in vivo. In this study, the effects of G17 and some related peptides on intracellular free Ca2+ in isolated pig parietal cells were studied. Both G17 and the synthetic peptide pentagastrin increased intracellular free Ca2+ in a dose-dependent manner over the concentration range 10(-9) to 10(-6) M, suggesting a specific action. The EC50 values were 3 X 10(-8) M for G17 and 8 X 10(-8) M for pentagastrin. The N-terminal tridecapeptide of G17 [(1-13)G17] did not have any effect on intracellular free Ca2+, nor was it able to inhibit the action of G17. A glycine-extended gastrin [(5-17)G17-Gly)] elicited a small but significant increase in intracellular free Ca2+ although only at 10(-6) M. This increase was approximately 20% of that obtained with a similar concentration of G17. Sequential incubations with (5-17)G17-Gly and G17 showed that both peptides increased the intracellular free Ca2+ through the same mechanisms.
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PMID:The effects of various gastrins on intracellular free Ca2+ in isolated pig parietal cells. 275 May 35

The 37 residue peptide YG (aPY), isolated from anglerfish endocrine pancreas, bears distinct sequence homology to the pancreatic polypeptide family of hormones. However, instead of a carboxyl-terminal tyrosine-amide, aPY has a free carboxyl-terminus ending with glycine. Towards studying the structure-activity relationship of this hormone, we have synthesized aPY by solid phase methodology using Boc-amino acid derivatives and phenylacetamidomethyl resin. The crude peptide was purified to homogeneity in 20% yield by reversed phase chromatography. The purified peptide had the expected amino acid composition and sequence, and was found to be identical with the natural aPY by analytical HPLC and peptide mapping of proteolytic digests. Neither the snythetic nor the natural aPY exhibited the characteristic vasoconstrictor activity of the related pancreatic polypeptide family of hormones. However, [Des37-Gly]-aPY, isolated from the anglerfish pancreas, caused vasoconstriction in rats. Based on these results and by analogy to the glycine-extended gastrin peptides, it may be suggested that aPY is a precursor of a biologically active peptide, namely [Des37-Gly]-aPY-amide.
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PMID:Glycine-extended anglerfish peptide YG (aPY) a neuropeptide Y (NPY) homologue may be a precursor of a biologically active peptide. 278 Apr 17

Homologues to the cholecystokinin (CCK)-gastrin peptide family have been cloned from Drosophila. The CCK-like precursor found in Drosophila has been designated drosulfakinin (DSK). Genomic and cDNA clones corresponding to the Drosophila neuropeptide precursor encode for three putative peptides. The three peptides (DSK-0, Asn-Gln-Lys-Thr-Met-Ser-Phe-Gly; DSK-I, Phe-Asp-Asp-Tyr-Gly-His-Met-Arg-Phe-Gly; DSK-II, Gly-Gly-Asp-Asp-Gln-Phe-Asp-Asp-Tyr-Gly-His-Met-Arg-Phe-Gly) are flanked by prohormone processing sites and contain C-terminal glycyl residues, a potential amidation site. Two of the peptides, DSK-I and DSK-II, are homologous to CCK-gastrin peptides. Each of the two homologues include a CCK-gastrin-like C-terminal pentapeptide and a conserved sequence corresponding to the sulfated tyrosine in bioactive CCK. The third peptide encoded by the drosulfakinin precursor represents a novel peptide. In situ tissue hybridization indicates the presence of the transcript in the adult head. Chromosomal localization maps the gene to the third chromosome near 81F.
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PMID:Identification and characterization of a Drosophila homologue to the vertebrate neuropeptide cholecystokinin. 284 22

Possible biologically active (receptor-bound) conformations of peptides derived from cholecystokinin (CCK) have been deduced using conformational analysis combined with comparative studies of their biological specificities. Two peptides, the completely active carboxyl terminal heptapeptide from CCK (CCK-7), whose sequence is Tyr-Met-Gly-Trp-Met-Asp-Phe-NH2, and the carboxyl terminal heptapeptide from cerulein (CER-7) which has the same sequence as for CCK-7 except for replacement of Met 2 with a Thr 2, both stimulate peripheral receptors in gall bladder, pancreas, and pylorus in the gastrointestinal system. In contrast, two other very similar peptides, the last four residues of CCK (CCK-4) whose sequence is Trp-Met-Asp-Phe-NH2, and the carboxyl terminal hexapeptide of little gastrin (LGA-6, Tyr-Gly-Trp-Met-Asp-Phe-NH2, i.e., residue 2 deleted relative to CCK-7 and CER-7 sequences), interact specifically with gastrin receptors and not at all or very weakly with peripheral receptors. All of these peptides react with CCK receptors in the central nervous system, especially in forebrain. The results in the GI tract suggest that the peptides active on peripheral receptors adopt structures that are significantly different from those of the peptides that interact with gastrin receptors. We have generated all of the many low energy conformations for each of these peptides. By retaining only the conformations that are the same for peptides within the same group and then rejecting those resulting conformations that are the same for the peptides in the two different groups, we can greatly reduce the possible active conformations for the peptides within each class.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Conformational analysis of possible biologically active (receptor-bound) conformations of peptides derived from cholecystokinin, cerulein and little gastrin and the opiate peptide, Met-enkephalin. 285 38

We recently identified carboxyl-terminally extended progastrin posttranslational processing intermediates in G cells of the gastric antrum and demonstrated that they are cosecreted with gastrin. To determine the physiological significance of these intermediates, we examined the biological activity of two synthetic gastrin precursor analogues that correspond to hexagastrin with carboxyl-terminal extensions, Tyr-Gly-Trp-Met-Asp-Phe-Gly (GL-7) and Tyr-Gly-Trp-Met-Asp-Phe-Gly-Arg-Arg (GL-9) on gastric parietal and D cells isolated from canine fundic mucosa. Both analogues were as efficacious as gastrin heptadecapeptide in displacing 125I-[Leu15]gastrin from binding sites on the two cell types and in stimulating [14C]aminopyrine uptake by parietal cells and somatostatin release from D cells. However, both analogues were 10(4)- to 10(5)-fold less potent than gastrin heptadecapeptide in these activities. Our results indicate that progastrin processing intermediates do not have physiologically relevant actions under normal circumstances and support the notion that carboxyl-terminally amidated peptides such as gastrin require the amide moiety for biological activity.
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PMID:Biological activity of progastrin posttranslational processing intermediates. 288 87

Glycine-extended intermediates of peptide processing serve as substrates for carboxyl-terminal amidation, hence activation, of many brain-gut peptides. To explore the dynamics of accumulation and secretion of these important intermediates we utilized primary cultures of canine antral mucosal G-cells as a model system. Glycine-extended progastrin processing intermediates (G-Gly) accumulated rapidly in G-cells cultured in ascorbate-deficient media, exhibiting a fourfold increase over a 51-h culture period, while gastrin content fell to less than half of the initial level. In contrast, G-cells cultured in ascorbate-supplemented media accumulated G-Gly at a relatively low rate, while gastrin was preserved at a higher level. Under either condition, G-Gly and gastrin were progressively released into the culture media. The release of both immunoreactivities could be stimulated by bombesin and inhibited by somatostatin in similar fashion. By electron microscopy, the cultured G-cells exhibited no ultrastructural alterations. These data suggest that 1) the cellular homeostasis of G-Gly is regulated by the activity of an ascorbate-dependent amidation enzyme similar to one previously described in pituitary tissues, 2) carboxyl-terminal amidation is not an obligatory step for secretion of gastrin, and 3) the proportions of gastrin and G-Gly cosecreted from G-cells reflect their proportional accumulation within G-cell secretory granules. The physiological relevance of the released G-Gly has yet to be determined.
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PMID:Glycine-extended progastrin processing intermediates: accumulation and cosecretion with gastrin. 288 66

To identify and characterize the subcellular topography of glycine-extended pro-gastrin-processing intermediates (G-Gly) in human antral mucosa, we performed an electron microscopic immunocytochemical study using region-specific antisera generated against the synthetic peptide, Tyr-Gly-Trp-Met-Asp-Phe-Gly (GL7), and C-terminal-specific anti-gastrin antisera. As has been previously reported, G-cells contained both electron-dense and electron-lucent granules, with a range of intermediate forms. Gastrin immunoreactivity was demonstrated in almost all granules of each type, whereas anti-GL7 antisera immunostained chiefly electron-dense granules. The relative ratio of GL7/gastrin granules varied among different cells but was approximately 1:10 on average. Other cytoplasmic organelles were devoid of specific labeling for GL7 or gastrin. As we have assumed that G-Gly serves as the immediate precursor for each molecular form of gastrin, electron-dense granules with high labeling for GL7 are regarded as the principal site for conversion of G-Gly to gastrin. This speculation supports many previous reports that electron-dense granules are immature and that the granules become less electron-dense with maturation.
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PMID:Intracellular topography of glycine-extended pro-gastrin-processing intermediates in human antral mucosa: an electron-microscopic immunocytochemical study. 291 20

Gallbladders removed at cholecystectomy are a potentially useful source of human receptor for the gastrointestinal peptide hormone cholecystokinin (CCK). Seven healthy gallbladders (removed incidentally at time of resection of hepatic metastases) and 50 diseased gallbladders were studied. Cholecystokinin radioligand binding to an enriched plasma membrane preparation from these tissues was shown to be rapid, reversible, temperature-dependent, saturable, specific, and high-affinity. Computer analysis of equilibrium binding data using the Ligand program best fit a single class of binding sites with Kd = 1.0 +/- 0.1 nM (mean +/- SEM). This was similar in health and disease, with no apparent differences related to age, gender, or body habitus. The structural specificity for binding to this site correlated well with relative potencies for CCK-gastrin peptides to stimulate gallbladder contraction. To biochemically characterize this receptor, we used a battery of reagents, including "long" (125I-Bolton Hunter-CCK-33) and "short" 125I-D-Try-Gly-[(Nle28,31)CCK-26-33] probes that were cross-linkable through their amino terminus and a monofunctional probe with a photolabile group at its carboxyl terminus 125I-D-Tyr-Gly[(Nle28,31,pNO2-Phe33)CCK-26-33]. All probes specifically labeled a human gallbladder muscularis protein of Mr = 85,000-95,000, which was also independent of diagnosis. Labeling of this band was inhibited in a concentration-dependent manner by CCK-8 and by L-364,718. Thus, the CCK receptor present on the very common surgically removed human gallbladder is functionally and biochemically intact and is useful for further characterization.
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PMID:Functional and biochemical characterization of the human gallbladder muscularis cholecystokinin receptor. 292 56


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