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)

The indirect immunofluorescence technique was used to demonstrate a substance reacting with gastrin antisera in the brain of Xenopus laevis. Immunoreactive material was found in two sites: (1) In the caudal hypothalamus more precisely in the nucleus infundibularis ventralis, (NIV) of the pars ventralis of the tuber cinereum, (PVTC). The fluorescent axons of the reactive parikarya of the NIV give rise to two symmetrical tracts which run rostro-ventrally and join, in the infundibular floor, the preoptico-hypophysial tract, where they form an uneven median tract coursing caudally and running along the medio-tuberal area before entering the external zone of the median eminence. (2) In the anterior preoptic area (APOA), where numerous nerve fibers and endings form a dense network near the preoptic recess. The exact origin of these terminals has not yet been determined. Control of immunohistochemical specificity shows that the labeling by gastrin antisera is suppressed by gastrin (2--17), but also by cholecystokinin (CCK) and pentagastrin (Peptavlon). These results indicate that the immunoreactive substance revealed belongs to the gastrin group and has an antigenic determinant composed of the amino acid sequence or a protion thereof common to gastrin, CCK and Peptavlon (Trp-Met-Asp-Phe). It should be emphasized that, in the brain of Xenopus laevis, both gastrin-immunoreactive sites correspond to the sites of uptake of steroid hormones (Kelley et al., 1975; Morrell et al., 1975).
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PMID:Immunohistochemical localization of a gastrin-like peptide in the brain of an amphibian, Xenopus laevis Daud. 38 28

Evidence is presented that minigastrin is the C-terminal tetradecapeptide amide of gastrin and not the tridecapeptide amide as previously reported. Synthesis of the tetradecapeptide amide sequence, Trp-Leu-[Glu]5-Ala-Tyr-Gly-Trp-Met-Asp-Phe-Nh2, was achieved by a series of fragment couplings which were mediated by the dicyclohexylcarbodiimide procedure in presence of either N-hydroxysuccinimide or 1-hydroxybenzotriazole. Purification of all intermediate fragments, and of the final protected tetradecapeptide amide, was by Sephadex LH-20 chromatography. Removal of the protecting groups was effected by treatment with 90% trifluoroacetic acid in the presence of a large excess of scavengers. Purification by ion-exchange chromatography afforded the pure tetradecapeptide amide. This material had full physiological activity.
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PMID:Minigastrin; corrected structure and synthesis. 76 48

Two derivatives of the C-terminal tripeptide of gastrin devoid of -NH2 from the phenylalanyl residue and of -COOH from the aspartic acid, MBOC-Met.Asn.Phe-OH (I) and MBOC-Met.Asp-OBenz.Phe-OMe (II), stimulated gastric acid secretion in the dog when infused intravenously at doses of 100 to 400 mug/kg-hr. Maximal responses induced by I and II were about 30-40% of that induced by the C-terminal tetrapeptide of gastrin. At a dose of 600 mug/kg-hr, I had an inhibitory action while II initially augmented and then inhibited acid production. Neither the C-terminal amide nor the carboxyl group of the aspartyl residue is essential for the gastric stimulatory activity of gastrin peptides.
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PMID:Dispensability of both the amide of phenylalanine and the carboxyl group of aspartic acid for the stimulation of gastric acid secretion by gastrin peptides in dogs. 83 7

Tertiary structures of gastrin-like tetrapeptide Trp-Met-Asp-Phe-NH2 and those substituted by Leu, Val or Gly for Met are studied. The lowest energy conformations of the side chains when the back bone is fixed in alpha-helix are obtained by modified minimization algorithm. It is suggested that protein folding proceeds in the accessible conformation space as a self-organization process leading to minimum energy conformation in this space.
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PMID:Tertiary structures of gastrin-like tetrapeptides. 99 44

High-resolution gel chromatography monitored by a sensitive radioimmunoassay for gastrin has disclosed that gastrin circulates in twenty different components. Since the assay is specific for the biological active sequence of gastrin (-Trp-Met-Asp-PheNH2), we conclude that all the twenty circulating molecular forms of gastrin encountered in this study may participate in the regulation of gastric acid secretion. There are two dominating forms of gastrin in serum: gastrin-34-like components and gastrin-17-like components. The former constituted 60% and the latter constitutes approximately 30% of the immunoreactive gastrins. We suggest that extragastrointestinal conversion of gastrin-17, released from tissue, is an important source of gastric-34-like components. Such conversion has been observed in intact man and pig. Studies with the isolated perfused porcine liver indicate that the liver is important in the metabolism of gastrin-17, and that conversion may be a hepatic function.
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PMID:The heterogeneity of gastrin, with reference to conversion of gastrin-17. 105 77

The term cholecystokinin (CCK) refers to a family of related peptides whose members play hormonal roles in the gastro-intestinal tract. The sulfated octapeptide CCK-8 [Asp-Tyr(SO3H)-Met-Gly-Trp-Met-Asp-Phe-NH2] is also abundant throughout the central nervous system where it satisfies the criteria for a neurotransmitter. CCK interacts with at least two types of receptor called CCK-A and CCK-B receptors. These binding sites can be distinguished on the basis of their affinities for different molecular forms of CCK. Moreover, selective nonpeptide antagonists have been developed for CCK-A and CCK-B receptors. CCK-A receptors occur predominantly at the peripheral level where they are responsible for the digestive effects of CCK: intestinal and biliary smooth muscle contraction, pancreatic enzyme secretion, trophic effects on gastric and intestinal mucosa and regulation of feeding. Some brain CCK-receptors belong to the A-type, but the majority of them are CCK-B receptors. High densities of brain CCK-B receptors are present in cortical and limbic areas such as the amygdala and the hippocampus. At the peripheral level, CCK-B receptor antagonists are active on gastrin receptors, and these two receptors are similar if not identical. Experimental evidence suggests involvement of brain CCK processes in 4 domains: modulation of dopaminergic function, control of pain sensation, anxiety and memory formation. Thus, CCK-B antagonists may be useful to treat certain neuropathological conditions associated with CCK dysfunction.
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PMID:[Cholecystokinins and their receptors. Functional aspects]. 130 46

1. Two novel insect myotropic peptides termed neosulfakinin-I (Neb-SK-I) and neosulfakinin-II (Neb-SK-II) were isolated from the heads of 42 thousand fleshflies, Neobellieria bullata (Diptera, Sarcophagidae). 2. A series of four, high-performance liquid chromatographic (HPLC), fractionations performed on columns with different characteristic features yielded two purified biologically active, hindgut motility stimulating fractions, suitable for amino acid sequence analysis. 3. The proposed sequences for the two peptides are: Phe-Asp-Asp-Tyr-Gly-His-Met-Arg-Phe-(NH2), (Neb-SK-I) and X-X-Glu-Glu-Gln-Phe-Asp-Asp-Tyr-Gly-His-Met-Arg-Phe-(NH2), (Neb-SK-II). 4. These sulfakinins exhibit very high homology to putative drosulfakinin sequences which, however, have not yet been isolated, but were deduced from a cloned Drosophila gene encoding these peptides. 5. Here we provide the first evidence for the expression of such peptides present in Dipterans. 6. Insect sulfakinins show structural identities with the hormonally-active portion of vertebrate gastrin II-, cholecystokinin- and caerulin-related peptides and they share common carboxy terminal sequences with invertebrate/vertebrate peptides of the FMRFamide peptide family.
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PMID:Isolation and primary structure of two sulfakinin-like peptides from the fleshfly, Neobellieria bullata. 136 Mar 67

Various tRNA transcripts were constructed to study the identity elements of Escherichia coli tRNA(Asp). Base substitutions from G34 to U34 at the first position of the anticodon, and from U35 to A35 at the second, severely impaired the aspartate charging activity. The activity was also decreased, but in a more moderate fashion, by base changes at G2-C71, C36 and C38. Identity nucleotides of tRNA(Asp) are distributed in a different fashion between E. coli and yeast, which occur at the second base pair of the acceptor stem, G10-U25 base pair in the D-stem and 3' half of the anticodon loop.
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PMID:Escherichia coli tRNA(Asp) recognition mechanism differing from that of the yeast system. 147 58

Binding to gastrin receptors and gastric acid secretion experiments were performed with gastrin derivatives modified at the C-terminal tetrapeptide amide from HG-13 sequence. 1. When the ultimate phenylalanine amide was replaced by a phenethylester or a phenetylamide moiety, the resulting compound bound to gastrin receptors (Kd approximately 10 nM) and exhibited antagonist activity on gastrin-induced acid secretion in the anesthetized rat. 2. Changing the peptide bond between Trp and Leu residues to a -omega(CH2-NH)- bond resulted in a compound which also bound to gastrin receptors (Kd approximately 10 nM) but presented agonist activity on acid secretion in the rat. In contrast, when the peptide bond between Leu and Asp residues was replaced by a -omega(CH2-NH)- bond, the resulting compound was devoid of any affinity for gastrin receptor (Kd greater than 10(-6) M) and of any biological activity. 3. The HG-13 derivatives were synthesized in sulfated and unsulfated forms: O-sulfation of the HG-13 tyrosine residue did not change its intrinsic in vivo activity but enhanced its affinity for gastrin receptors (Kd approximately 0.3 nM). On the contrary, O-sulfation of the various chemically modified HG-13 had no significant effect in either in vitro or in vivo experiments. 4. Finally, no significant difference between binding on parietal (F3) and nonparietal (F1) cells was observed, in agreement with the presence of a gastrin-type receptor in these two cell populations.
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PMID:Biological effects of human gastrin I and II chemically modified at the C-terminal tetrapeptide amide. 152 64

A single-strand-specific nuclease from rye germ (Rn nuclease I) was characterized as a tool for secondary and tertiary structure investigation of RNAs. To test the procedure, yeast tRNA(Phe) and tRNA(Asp) for which the tertiary structures are known, as well as the 3'-half of tRNA(Asp) were used as substrates. In tRNA(Phe) the nuclease introduced main primary cuts at positions U33 and A35 of the anticodon loop and G18 and G19 of the D loop. No primary cuts were observed within the double stranded stems. In tRNA(Asp) the main cuts occurred at positions U33, G34, U35, C36 of the anticodon loop and G18 and C20:1 positions in the D loop. No cuts were observed in the T loop in intact tRNA(Asp) but strong primary cleavages occurred at positions psi 55, C56, A57 within that loop in the absence of the tertiary interactions between T and D loops (use of 3'-half tRNA(Asp)). These results show that Rn nuclease I is specific for exposed single-stranded regions.
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PMID:Structural specificity of Rn nuclease I as probed on yeast tRNA(Phe) and tRNA(Asp). 154 62


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