Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oxytocin (OT) was synthesized employing the solid phase method. Resins made of copolymers of polystyrene-1%-crosslinked with divinylbenzene gave better yields (73-95%) of Z-Cys(Bzl)-Tyr(Bzl)-Ile-Gln-Asn-Cys(Bzl)-Pro-Leu-Gly-NH2 (I) than 2%-crosslinked resins (10--56%). Reduction of I with Na-liq.NH3 and oxidation with I2-MeOH at -40 degrees minimized dimer and polymer formation, and resulted in good yields (49--54%) of OT. The large volumes of MeOH required when several grams of I are reduced and then oxidized were rapidly evaporated in vacuo, and the residue was desalted by dissolving the peptide in a small volume of glacial acetic acid and filtering to remove the salt. OT was purified by adsorption chromatography on a silica gel column with combinations of MeOH-CHCl3 of graded polarity. Oxytocin elutes with 33% MeOH-CHCl3. After two purification steps by adsorption chromatography, the resulting OT was found to be homogeneous. The hormone was characterized chemically and found to be active biologically.
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PMID:Synthesis of oxytocin using iodine for oxidative cyclization and silica gel adsorption chromatography for purification. 42 90

[1-Deaminopenicillamine,4-threonine]oxytocin was prepared in duplicate from S-benzyl-3-mercapto-3,3-dimethylpropanoyl-Tyr(Bzl)-Ile-Thr(Bzl)-Asn-Cys(Bzl)-Pro-Leu-Gly-NH2 (I) by removal of the Bzl-protecting groups with Na-NH3, followed by cyclization of the resulting disulfhydryl compound with K3Fo(CN)6. The analogue was purified by desalting on Sephadex G-15 in 50% acetic acid and gel filtration of Sephadex G-15. The protected peptide I was synthesized (a) by the solid-phase method and (b) by a combination of solid-phase synthesis and an [8 + 1] coupling in solution. The analogue has no detectable agonist activity in rat vasopressor or isolated rat uterus assays. It has an antivasopressor pA2 of 6.67 +/- 0.09. It is a potent inhibitor of the in vitro oxytocic response to oxytocin and has a pA2 value of 7.46 +/- 0.04. (Material from the repeat synthesis has a pA2 value of 7.59 +/- 0.08.) Thus the substitution of threonine for glutamine in the antagonist [1-deaminopenicilliamine]oxytocin (pA2, 7.14 +/- 0.05) has effected a twofold increase in inhibitory potency. [1-deaminopenicillamine,4-threonine]oxytocin is one of the most potent inhibitors of oxytocin known to date.
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PMID:[1-Deaminopenicillamine,4-threonine]oxytocin, a potent inhibitor of oxytocin. 62 12

Bovine neurophysin-I (bNP-I) is the first neurophysin protein which contains histidine and possesses an acidic COOH-terminal segment for which the complete amino acid sequence is presented: NH2-Ala-Val-Leu-Asp-Leu-Asp-Val-Arg-Thr-Cys-Leu-Pro-Cys-Gly-Pro-Gly-Gly-Lys-Gly-Arg-Cys-Phe-Gly-Pro-Ser-Ile-Cys-Cys-Gly-Asp-Glu-Leu-Gly-Cys-Phe-Val-Gly-Thr-Ala-Glu-Ala-Leu-Arg- Cys-Gln-Glu-Glu-Asn-Tyr-Leu-Pro-Ser-Pro-Cys-Gln-SerGly-Gln-Lys-Pro-Cys-Gly-Ser- Gly-Gly-Arg-Cys-Ala-Ala-Ala-Gly-Ile-Cys-Cys-Ser-Pro-Asp-Gly-Cys-His-Glu-Asp-Pro-Ala-Cys-Asp-Pro-Glu-Ala-Ala-Phe-Ser-Leu-COOH. Determination of the structure was greatly facilitated by new procedures used for the isolation of bNP-I and of its tryptic peptide fragments. bNP-I isolated from freshly frozen bovine posterior pituitaries is composed of 93 residues, but some preparations contain neurophysin protein with NH2- and COOH-terminal truncated sequences. bNP-I differs from bovine neurophysin-II, the second major neurophysin of cow, in 20 residue positions, and several of the differences cannot be accounted for by single nucleotide replacements in the genes coding for these two neurophysin proteins. The results reported in this study support our earlier hypothesis that neurophysin-gene duplication preceded species divergence.
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PMID:Complete amino acid sequence of bovine neurophysin-I. A major secretory product of the posterior pituitary. 67 Jan 74

The solution conformation of a retro-D analogue of tocinamide H-D-Cys-D-Asn-D-Gln-D-aIle-D-Tyr-NHCH2CH2S was examined using proton magnetic resonance and circular dichroism spectroscopy. The observations support major contributions to the conformational distribution from structures with a type I beta turn in the sequence D-Asp-D-Gln-D-aIle-D-Tyr. This is topologically similar to the beta turn proposed for oxytocin, L-Tyr-L-Ile-L-Gln-L-Asn, but with the polarity of the CONH groups reversed along the chain; the peptide is, however, hormonally inert. In conjuction with nuclear magnetic resonance data, the circular dichroism spectra are interpreted to indicate that the region of the peptide ring near the disulfide occurs in at least two different conformations. One of the side-chain carboxamides, probably that of asparagine, appears to be intramolecularly associated rather than freely exposed to solvent.
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PMID:Solution conformation of a retro-D analogue of tocinamide. 95 44

[1-Beta-mercapto-beta,beta-pentamethylenepropionic acid]oxytocin was prepared from beta-Mpa(beta-(CH2)5)(Bzl)-Tyr(Bzl)-Ile-Gln-Asn-Cys(Bzl)-Pro-Leu-Gly-NH2 by removal of the Bzl-protecting groups with Na-NH3 followed by cyclization of the resulting disulfhydryl compound with K3Fe(CN)6.The analog was purified by desalting on Sephadex G-15 in 50% HOAc and gel filtration on Sephadex G-25 and LH-20. The protected intermediate above was synthesized from Z-Cys(Bzl)-Pro-Leu-Gly-NH2 by the stepwose p-nitrophenyl ester method using Nalpha-Boc protection at the penta-, hexa-, and octapeptide stages. The analog was found to be a potent inhibitor of the oxytocic and avian vasodepressor effects of oxytocin (pA2 values of 7.43 and 8.30, respectively) but was only a weak inhibitor of the rat pressor effect of 8-lysine-vasopressin. The rat antipressor potency of [1-deaminopenicillamine]oxytocin was also determined in this study: pA2 = 6.27. Of the alkyl-substituted 1-position analogs of oxytocin studied so far, [1-beta-mercapto-beta,beta-pentamethylenepropionic acid]oxytocin is the most potent antioxytocic agent.
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PMID:[1-Beta-mercapto-beta,beta-pentamethylenepropionic acid]oxytocin, a potent inhibitor of oxytocin. 113 19

For the synthesis of [1-L-penicillamine,4-L-leucine]oxytocin (2), Z-Tyr(Bzl)-Ile-Leu-Asn-Cys(Bzl)-Pro-Leu-Gly-NH2 was treated with anhydrous HBr, and the resulting partially deprotected octapeptide was coupled with Z-penicillamine(Bzl) in a condensation reaction mediated by dicyclohexylcarbodiimide and 1-hydroxybenzotriazole. The protected nonapeptide Z-penicillamine(Bzl)-Tyr-Ile-Leu-Asn-Cys(Bzl)-Pro-Leu-Gly-NH2 was treated with Na in NH3 and the resulting disulfhydryl compound was subjected to oxidative cyclization in H2O-CH3OH with ICH2CH2I, Purification of 2 was effected by partition chromatography and gel filtration. The analog possesses antioxytocic and antiavian vasodepressor pA2 values of 6.77 and 7.21, respectively, and has no antipressor or anti-ADH activity. Its biological activity spectrum is qualitatively identical with that of [1-penicillamine]oxytocin. In contrast to the marked natriuretic-diuretic and anti-antidiuretic activity of [Leu4]oxytocin, 2 exhibits none of these effects on the rat kidney.
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PMID:Synthesis and pharmacological properties of [1-L-penicillamine,4-L-leucine]oxytocin. 115 79

[4-Phenylalanine]oxytocin was prepared from Z-Cys(Bzl)-Tyr(Bzl)-Ile-Phe-Asn-Cys(Bzl)-Pro-Leu-Gly-NG2 (4) by deprotection with Na in NH3 followed by cyclization of the resulting disulfhydryl compound with ICH2CH2I. The protected peptide 4 was prepared from Boc-Asn-Cys(Bzl)-Pro-Leu-Gly-NH2 by the stepwise solution method. Coupling was effected by a modification of the dicyclohexylcarbodiimide-1-hydroxybenzotriazole preactivation method wherein the precipitate of dicyclohexylurea is removed by filtration prior to mixing of the amino and carboxyl components. The analog was found to be an effective inhibitor of the antidiuretic (ADH) response to exogenous arginine-vasopressin. It produced marked diuresis in the anti-ADH assay at approximately the same dose level as does [Leu4]oxytocin but, in contrast to [Leu4]oxytocin, showed natriuretic activity only at relatively high dose levels. In addition, [Phe4]oxytocin exhibited 0.15% of the oxytocic potency of oxytocin, weak antiavian vasodepressor activity (pA2 = 6.93), and no measurable rat pressor activity.
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PMID:(4-Phenylalanine)oxytocin, an inhibitor of the antidiuretic effect of 8-arginine-vasopressin. 115 80

[1-Beta-Mercaptopropionic acid,2-(3,5-dibromo-L-tyrosine)]oxytocin was synthesized from a protected polypeptide intermediate that had been prepared by the condensation of S-ethylcarbamoyl-beta-mercaptopropionyl-3,5-dibromotyrosine with H-Ile-Gln-Asn-Cys(Ec)-Pro-Leu-Gly-NH2, using dicyclohexylcarbodiimide in dimethylformamide. The ethylcarbamoyl (Ec) protecting groups were removed by refluxing NH3, and the resulting disulfhydryl peptide was oxidatively cyclized to the corresponding disulfide by ICH2CH2I. Purification of the analog was effected by partition chromatography and gel filtration. The analog possesses antioxytocic (pA2 = 7.05) and antiavian vasodepressor (pA2 = 7.44) activities but has neither agonist nor antagonist activity in the rat pressor assay.
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PMID:(1-Beta-mercaptopropionic acid, 2-(3,5-dibromo-L-tyrosine))oxytocin, a potent inhibitor of oxytocin. 115 88

Interactions of several proteins with glutathione-insulin transhydrogenase (GIT) have been investigated by determining their ability to inhibit degradation of 125I-labeled insulin catalyzed by GIT. The inhibition by every insulin analog (des-Asn-des-Ala-pork insulin, desoctapeptide-pork insulin, des-Ala-pork insulin, pork insulin, proinsulin, and guinea pig insulin) was competitive vs. competitive vs. insulin indicating that they function as alternate substrates. The insulin analogs with the least hormonal activity showed the highest potency as inhigitors of insulin degradation. Whereas native ribonuclease and lysozyme showed little or no inhibition, their scrambled forms (i.e. reduced and randomly reoxidized) showed competitive inhibition with a potency greater than that of insulin. These results suggest that the conformation of the substrate or inhibitor is probably the major factor in determining the specificity for (or binding to) the enzyme. Studies withother peptide hormones showed competitive inhibition with vasopressin and oxytocin and noncompetitive inhibition with glycagon. The inhibition with growth hormone could be either competitive or noncompetitive. The inhibition by glucagon and growth hormone (physiologic antagonists of insulin) could serve as a control mechanism to modulate the activity of enzyme. The following showed very little or no inhibition; the native and scrambled form of pepsinogen, trypsin inhibitor of beef pancreas and of lima bean, C-peptide of pork proinsulin, and heptapeptide (B23-B29) of insulin.
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PMID:Interaction of insulin analogs, glucagon, growth hormone, vasopressin, oxytocin, and scrambled forms of ribonuclease and lysozyme with glytathione-insulin transhydrogenase (thiol: protein-disulfide oxidoreductase): dependence upon conformation. 117 Aug 77

The synthesis of the protected polypeptide precursor of [1-beta-mercapto-beta,beta-diethylpropionic acid,2-(3,5-dibromo-L-tyrosine)]oxytocin was performed in a stepwise manner by solution techniques. This analog of oxytocin has two modifications, each of which taken alone gives analogs which inhibit some of the pharmacological responses to oxytocin. The S-ethylcarbamoyl protecting groups of beta-Mpa(beta-Et2)(Ec)-Dbt-Ile-Gln-Asn-Cys(Ec)-Pro-Leu-Gly-NH2 were removed in refluxing liquid NH3, and the resulting disulfhydryl compound was oxidatively cyclized in H2O-MeOH with ICH2CH2I. Purification was effected by partition chromatography and gel filtration. The analog possesses antioxytocic (pA2 = 7.08) and antiavian vasodepressor (pA2 = 7.38) activities but has neither agonist nor antagonist activity in the rat pressor assay. These potencies are close to those exhibited by [1-beta-mercaptopropionic acid,2-(3,5-dibromo-L-tyrosine)]oxytocin but different from those of [1-beta-mercapto-beta,beta-diethylpropionic acid]oxytocin.
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PMID:Synthesis and some pharmacological properties of [1-beta-mercapto-beta,beta-diethylpropionic acid,2-(3,5-dibromo-L-tyrosine)]oxytocin. 119 81


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