Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

gamma-Endorphin is a naturally occurring biologically active peptide that is produced by an endopeptidase activity cleaving its precursor beta-endorphin. This enzyme was termed gamma-endorphin generating enzyme (gamma-EGE). In order to quantitate gamma-EGE activity by means of a simple and sensitive assay two synthetic peptides derived from the sequence surrounding the gamma-EGE cleavage site in beta-endorphin were tested as substrates. One of these peptides Ac-Val-Thr-Leu-Phe-Lys-NHCH3 fulfilled all criteria for a suitable gamma-EGE substrate. The peptide was exclusively cleaved at the correct bond for gamma-EGE upon incubation with brain synaptic membranes, and this cleavage was inhibited by the naturally occurring substrate beta-endorphin. The peptide was insensitive to cleavage by exopeptidases and cathepsin D. Addition of a 14C-labeled methyl group at the lysine residue of this peptide by reductive methylation did not alter its properties as a substrate for gamma-EGE activity. The use of the 14C-labeled peptide allowed sensitive quantitation of its radioactive products after simple separation by hydrophobic chromatography on minicolumns containing polystyrene beads. gamma-EGE activity increased linearly with a protein concentration and incubation time. This assay can be used for reliable quantitation of gamma-EGE activity and permits investigations on the regulation of gamma-endorphin production.
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PMID:Quantitation of the endopeptidase activity generating gamma-endorphin from beta-endorphin in rat brain synaptic membranes by a radiometric assay. 620 8

The isolation and complete purification of a human glycopeptide representing the major immunoreactive form of the pituitary NH2-terminal segment of pro-opiomelanocortin is presented. The complete sequence of this peptide was determined following CNBr fragmentation and it is shown to be 76 amino acids long. It bears an O-glycosylation site at Thr 45 and an N-glycosidic linkage at Asn 65. Compared to the reported genomic DNA sequence (Chang, A. C. Y., Cochet, M., and Cohen, S. N. (1980) Proc. Natl. Acad. Sci. U. S. A. 77, 4890-4894), one variation exists, namely Arg 22 replacing Gly 22. Two disulfide bridges linking Cys 2 to 8 and Cys 20 to 24 have been determined. Based on the sequence and disulfide bridge localization, a large degree of homology exists between the NH2-terminal sequence of the human peptide and all calcitonins, especially porcine calcitonin. The human NH2-terminal peptide is shown to stimulate the release of aldosterone from isolated cells of a human adrenal tumor, in at least equipotency to adrenocorticotropic hormone and the porcine NH2-terminal analogue, which is 100 times more potent than angiotensin II. Finally, this reported sequence completes that of the human DNA which was lacking the first 19 amino acids due to the presence of a 2-kilobase intron.
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PMID:Primary structure of the major human pituitary pro-opiomelanocortin NH2-terminal glycopeptide. Evidence for an aldosterone-stimulating activity. 626 33

Sequence analysis was performed of an ovine hypothalamic 41-residue polypeptide that had been postulated to be a putative corticotropin-releasing factor (CRF) because of its high intrinsic corticotropin releasing activity. The NH2-terminal 39 residues of CRF were determined by Edman degradation of 0.6-3.5 nmol of peptide in a Wittmann-Liebold modified Beckman 890C spinning cup sequencer with reverse-phase high-pressure liquid chromatography for the identification of amino acid phenylthiohydantoins (direct micro-sequence analysis). Evidence for residue 40 (isoleucine) was provided by direct micro-sequence analysis of 2.0 nmol of acetylated CRF selectively cleaved at its arginine residues by trypsin prior to analysis. The thermolytic COOH-terminal fragment isoleucyl-alanineamide was characterized as its dansyl derivative. Based on the analytical data, the following primary structure is proposed for ovine hypothalamic CRF: H-Ser-Gln-Glu-Pro-Pro-Ile-Ser-Leu-Asp-Leu-Thr-Phe-His-Leu-Leu-Arg-Glu-Val-Leu-Glu-Met-Thr-Lys-Ala-Asp-Gln-Leu-Ala-Gln-Gln-Ala-His-Ser-Asn-Arg-Lys-Leu-Leu-Asp -Ile-Ala-NH2. In agreement with this proposal, the synthetic replicate of CRF is highly potent in stimulating secretion of both corticotropin and beta-endorphin-like immunoactivities.
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PMID:Primary structure of corticotropin-releasing factor from ovine hypothalamus. 627 74

Beta-endorphin has been isolated from equine pituitaries. Its amino acid sequence is identical to that of ovine, bovine and camel beta-endorphins except for substitution of the threonine residue at position 6 by serine. The equine beta-endorphin has also been synthesized by the solid-phase method. In comparison with the human hormone, equine beta-endorphin was shown to possess 3 times the receptor-binding activity in rat membrane preparations and 1.6 times the analgesic potency in the mouse tail-flick assay.
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PMID:beta-Endorphin: isolation, amino acid sequence and synthesis of the hormone from horse pituitary glands. 628 Dec 4

A 41 amino acid peptide with high intrinsic corticotropin-releasing activity was isolated from 1000 bovine hypothalami by means of immunoaffinity chromatography, gel filtration, and two steps of reverse phase HPLC. The primary structure of the amino terminal 39 amino acids was characterized by gas phase sequence analysis. The sequence of the amidated carboxyl terminal dipeptide was established by digestion of the intact natural product with Staphylococcus aureus V8 protease, dansylation of the digest and comparative reverse phase liquid chromatography studies with the synthetic dansylated dipeptides Ile-Ala-NH2, Ile-Ala-OH, Ala-Ile-NH2 and Ala-Ile-OH. The complete structure of the bovine corticotropin-releasing factor was established as: Ser-Gln-Glu-Pro-Pro-Ile-Ser-Leu-Asp-Leu-Thr-Phe-His-Leu-Leu-Arg-Glu-Val- Leu- Glu-Met-Thr-Lys-Ala-Asp-Gln-Leu-Ala-Gln-Gln-Ala-His-Asn-Asn-Arg-Lys-Leu- Leu- Asp-Ile-Ala-NH2 using approximately 650 pmol of material.
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PMID:Isolation and characterization of the bovine hypothalamic corticotropin-releasing factor. 633 25

Sequence analysis was performed on a 41-residue polypeptide that has been identified as the predominant form of high intrinsic corticotropin-releasing activity of rat hypothalamus. The sequence of residues 1-39 of this corticotropin-releasing factor (CRF) was determined by Edman degradation of a partially purified peptide in a highly sensitive spinning cup sequencer after selective blocking of CRF or its main contaminant with o-phthalaldehyde. This approach was validated by peptide mapping of CRF of a highly purified preparation. Peptide mapping was accomplished with reverse-phase high-pressure liquid chromatography of CRF fragments obtained by digestion with clostripain. The identities of the fragments cleaved from CRF were established by chromatographic comparison with synthetic peptides, amino acid analysis, and Edman degradation. On the basis of these experiments, the primary structure of rat hypothalamic CRF was established to be H-Ser-Glu-Glu-Pro-Pro-Ile-Ser-Leu-Asp-Leu-Thr-Phe-His-Leu- Leu-Arg-Glu-Val-Leu-Glu-Met-Ala-Arg-Ala-Glu-Gln-Leu-Ala-Gln-Gln-Ala-His-Ser-Asn - Arg-Lys-Leu-Met-Glu-Ile-Ile-NH2. It is expected that the o-phthalaldehyde strategy will facilitate the sequence analysis of partially purified peptides containing proline residues.
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PMID:Sequence analysis of rat hypothalamic corticotropin-releasing factor with the o-phthalaldehyde strategy. 635 54

Homogenates of rat neurointermediate lobes were purified by centrifugation on a Percoll gradient. Lysates of the Percoll gradient fractions were incubated with a synthetic octapeptide and pentapeptide substrate (N-acetyl Lys-Arg-Tyr-Asn-Leu-Thr-Ser-Val-amide and N-acetyl Lys-Arg-Tyr-Asn-Leu-amide), and enzymatic characteristics were compiled. Early assays on nonamidated forms revealed carboxypeptidase activity, whereas with the amide derivatives no carboxypeptidase activity could be detected. These amide substrates were therefore used in all subsequent incubations. High levels of a Leu/Thr and Lys/Arg cleavage were present in fractions almost throughout the Percoll gradient. Cleavages at Tyr/Asn, Thr/Ser, and Arg/Tyr were localized at different regions of the Percoll gradient. Surprisingly, none of the five enzymatic activities appear to be localized in the secretory granule fractions as defined by the presence of immunoreactive beta-endorphin in the gradient. All of the five proteolytic activities have a basic pH optimum (pH 8-9), and four of them seem to be thiol proteases, as categorized by inhibitor studies. The fifth one, namely the Try/Asn cleavage, is more likely to be due to a metalloendopeptidase, since it is activated by Zn2+ and Co2+.
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PMID:Subcellular fractionation of pituitary neurointermediate lobes: revelation of various basic proteases. 643 Jun 76

A polypeptide was purified from rat hypothalamic extracts on the basis of its high intrinsic activity to release corticotropin (ACTH) from cultured rat anterior pituitary cells and its immunoactivity in a radioimmunoassay directed against the NH2 terminus (residues 4-20) of ovine hypothalamic corticotropin-releasing factor (CRF). Based on Edman degradation, peptide mapping, and amino acid analysis, the primary structure of this rat CRF was established to be: H-Ser-Glu-Glu-Pro-Pro-Ile-Ser-Leu-Asp-Leu-Thr-Phe-His-Leu-Leu-Arg-Glu-Val-Leu-Glu-Met-Ala-Arg-Ala-Glu-Gln-Leu-Ala-Gln-Gln-Ala-His-Ser-Asn-Arg-Lys-Leu-Met-Glu-Ile-Ile-NH2. The hypophysiotropic potency of synthetic rat CRF did not deviate significantly from the potencies of the isolated native peptide or of synthetic ovine CRF. The close structural relationship between rat and ovine hypothalamic CRF is indicated by an 83% sequence homology.
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PMID:Characterization of rat hypothalamic corticotropin-releasing factor. 660 20

A putative melanin-concentrating hormone was synthesized. This peptide, H-Asp-Thr-Met-Arg-Cys-Met-Val-Gly-Arg-Val-Tyr-Arg-Pro-Cys-Trp-Glu-Val-OH , stimulates melanin granule aggregation within teleost melanocytes at nanomolar concentrations as does the natural purified teleost pituitary preparation. In addition, this peptide stimulates melanin granule dispersion within melanocytes of frogs and lizards. The peptide has about one six-hundredth of the activity of alpha-melanocyte-stimulating hormone on frog and lizard melanocytes and is a full agonist.
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PMID:Synthesis of a cyclic melanotropic peptide exhibiting both melanin-concentrating and -dispersing activities. 660 33

The potencies of several opiates and opioid peptides for potentiating the synaptic activation of CA1 pyramidal cells were compared in the rat hippocampal slice preparation. Morphine and the opioid peptides [D-Ala2, D-Leu5]-enkephalin (DADL), beta-endorphin and Tyr-D-Ser-Gly-Phe-Leu-Thr (a delta agonist) caused a concentration-dependent shift to the left in the input-output curve constructed by plotting population spike amplitude (a measure of evoked firing) as a function of the dendritic field excitatory postsynaptic potential. The concentration-response curves for DADL and morphine had similar slopes and maxima, although the curve for morphine was biphasic due to the addition of a nonopiate effect that became apparent at higher concentrations (greater than or equal to 20 microM). The EC50 values were 68 nM for DADL and 3000 nM for morphine. The IC50 values of naloxone against equieffective concentrations of DADL and morphine were not significantly different. Perfusion of slices with a combination of nearly maximally effective concentrations of DADL and morphine resulted in an effect that was no greater than the maximum effect obtained by either drug alone. The results suggest that these opioids produce their actions through a common pathway. The rank order of potency to produce identical effects was DADL greater than Tyr-D-Ser-Gly-Phe-Leu-Thr greater than beta-endorphin greater than morphine. The kappa agonist ethylketocyclazocine was inactive at concentrations up to 10 microM. The data suggest that delta opioid receptors play a key role in the epileptiform action of these opiates in the CA1 region of the rat hippocampus. However, this opioid response may be different from those characterized in peripheral preparations because ethylketocyclazocine appears to be inactive in the hippocampal CA1 region.
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PMID:Pharmacological characterization of opioid effects in the rat hippocampal slice. 675 74


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