| 4968234 |
Surfactin, a crystalline peptidelipid surfactant produced by Bacillus subtilis: isolation, characterization and its inhibition of fibrin clot formation |
10.1016/0006-291x(68)90503-2. |
Biochem Biophys Res Commun |
Surfactin, a crystalline peptidelipid surfactant produced by Bacillus subtilis: isolation, characterization and its inhibition of fibrin clot formation
Abstract
|
| 5131162 |
The structure of nisin |
10.1021/ja00747a073. |
J Am Chem Soc |
The structure of nisin
Abstract
|
| 5788506 |
The molecular structure and some transport properties of valinomycin |
10.1016/0006-291x(69)90376-3. |
Biochem Biophys Res Commun |
The molecular structure and some transport properties of valinomycin
Abstract
|
| 6086290 |
Studies of the nature of the interaction between vasopressin and corticotropin-releasing factor on adrenocorticotropin release in the rat |
10.1210/endo-115-3-882. |
Endocrinology |
Studies of the nature of the interaction between vasopressin and corticotropin-releasing factor on adrenocorticotropin release in the rat
Abstract
- Arginine-vasopressin (AVP) acts on vasoconstriction and diuresis through two different types of receptors (V1 and V2, respectively). Since AVP also modifies ACTH release, we have attempted to determine which class of receptors mediates the capacity of AVP to increase ACTH secretion and to potentiate the effect of corticotropin-releasing factor (CRF) on the pituitary using two AVP antagonists: 1-deaminopenicillamine-2-(O-methyl)tyrosinearginine-vasopressin dPTyr(Me)-AVP, which blocks V1 receptors, and 1-beta-mercapto-beta,beta-cyclopentamethylene propionic acid)2-D-leucine-4-valinearginine vasopressin d(CH2)5DLeuValAVP, which interferes with V2 receptors. dPTyr(Me)AVP, but not d(CH2)5DLeuValAVP, inhibited the ACTH-releasing as well as the CRF-potentiating effects of both AVP and its antidiuretic analog 1-deamino-8-D-argininevasopressin (dDAVP). These results suggest that the actions of AVP and dDAVP on the corticotrophs is primarily mediated through V1 (pressor-like) receptors.
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| 6093780 |
Isolation of an evolutionarily conserved epidermal growth factor receptor cDNA from human A431 carcinoma cells. |
10.1016/0006-291x(84)90926-4 |
Biochem. Biophys. Res. Commun. |
Isolation of an evolutionarily conserved epidermal growth factor receptor cDNA from human A431 carcinoma cells.
Abstract
- Complementary DNA corresponding to total poly(A)+-RNA from the human A431 epidermoid carcinoma cell line was cloned in the phage expression vector lambda gt 11. An epidermal growth factor (EGF) receptor cDNA clone was obtained by screening of the expression library with a rabbit polyclonal antibody (IgG), raised to the purified A431 EGF receptor, in combination with [125I]protein A of S. aureus. The cloned cDNA was able to select, by hybridization, messenger RNA which was translated in Xenopus oocytes and yielded an immunoprecipitable EGF receptor protein of Mr = 160,000. The insert of this cDNA (phEGFR-1), is approximately 880 base pairs in length and encodes the carboxyterminal portion of the EGF receptor protein. Its sequence is evolutionarily conserved among vertebrates as shown by hybridization to unique chromosomal DNA sequences from human, baboon, dog, rat, mouse and frog.
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| 6094207 |
Centrally administered PGE2 inhibits gastric secretion in the rat by releasing vasopressin |
10.1016/0014-2999(84)90381-9. |
Eur J Pharmacol |
Centrally administered PGE2 inhibits gastric secretion in the rat by releasing vasopressin
Abstract
- The pituitary mechanism of the central inhibitory effect of PGE2 on gastric secretion was investigated in rats. The intravenous (i.v.) injection of neurointermediate lobe extracts but not of anterior lobe extracts inhibited gastric secretion in pylorus-ligated rats. The i.c.v. administration of 3 micrograms of PGE2 increased the plasma level of vasopressin but had no effect on plasma beta-endorphin/beta-lipotropin. The i.v. administration of 10 micrograms d(CH2)5Tyr(Me) AVP, a vasopressin antagonist, prevented the inhibition of gastric secretion induced by i.c.v. administration of 3 micrograms PGE2 to pylorus-ligated rats. The results indicate that the central antisecretory action of PGE2 is due to the release of vasopressin from the pituitary gland.
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| 6097525 |
Preferential binding to delta-receptors of the enkephalin-like tetrapeptide Tyr-Ile-Phe-Val. Electrophysiological and conformation studies |
10.1515/bchm2.1984.365.2.1227. |
Hoppe Seylers Z Physiol Chem |
Preferential binding to delta-receptors of the enkephalin-like tetrapeptide Tyr-Ile-Phe-Val. Electrophysiological and conformation studies
Abstract
- The technique of microiontophoresis was used to study the effects of leucine-enkephalin ( Leuenkephalin) and the tetrapeptide Tyr-Ile-Phe-Val on spontaneous and evoked activity of guinea-pig hypothalamic neurons. The inhibitory effects of the tetrapeptide were similar to those of Leuenkephalin on some neurons. However, in other cases, Leuenkephalin was inhibitory whereas Tyr-Ile-Phe-Val was without effect. These data and the fact that naloxone caused a different antagonism of inhibitory effects by these two peptides suggest the existence of two types of opiate receptors on some hypothalamic neurons and that Tyr-Ile-Phe-Val preferentially binds to delta-receptors. Conformational features of Tyr-Ile-Phe-Val have been established by 1H-NMR spectroscopy and were found to be in accordance with the above considerations. The peptide has a peculiar folded conformation called gamma-turn. Due to the restricted flexibility of this structure, the aromatic moieties (Tyr and Phe) and the hydrophobic (Val) or hydrophilic (terminal NH2 and CO2H) parts are positioned in a specific spatial relationship which can be related to an optimal binding to delta-receptors.
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| 6105610 |
Selective effect of some somatostatin analogs on glucagon as opposed to insulin release in rats in vivo |
10.1016/0026-0495(80)90194-8. |
Metabolism |
Selective effect of some somatostatin analogs on glucagon as opposed to insulin release in rats in vivo
Abstract
- Cyclic somatostatin, at a dose of 700 but not 70 ng/kg/min, inhibited arginine-induced insulin and glucagon release as well as glucose stimulated insulin release in rats in vivo. Three somatostatin (S-S) analogs (D-Cys14-S-S, D-Trp8-D-Cys14-S-S and Ala2-D-Trp8-D-Cys14-S-S), at a dose of 70 ng/kg/min, suppressed arginine-induced glucagon but not insulin release. At the same dose, the first two of these analogs had no effect on glucose-induced insulin release, while the third one. Ala2-D-Trp8-D-Cys14-somatostatin, enhanced insulin release induced by glucose. A fourth analog, D-Trp8-somatostatin, was more potent than somatostatin with regard to arginine stimulated insulin and glucagon release, and equipotent with somatostatin with respect to glucose stimulated insulin release. These studies show, firstly, that the inhibitory effect of somatostatin analogs on arginine induced insulin release may be different from that when glucose is used as a stimulant and, secondly, that Ala2-D-Trp8-D-Cys14-somatostatin inhibits arginine-induced glucagon release while enhancing insulin release on glucose stimulation.
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| 6106477 |
Conformational energy studies of the growth hormone inhibitor, cyclo (Aha-Cys-Phe-D-Trp-Lys-Thr-Cys) |
10.1016/0006-291x(80)90704-4. |
Biochem Biophys Res Commun |
Conformational energy studies of the growth hormone inhibitor, cyclo (Aha-Cys-Phe-D-Trp-Lys-Thr-Cys)
Abstract
|
| 6106638 |
Conformational studies of somatostatin and selected analogues by Raman spectroscopy |
10.1111/j.1399-3011.1980.tb02912.x. |
Int J Pept Protein Res |
Conformational studies of somatostatin and selected analogues by Raman spectroscopy
Abstract
- Laser Raman spectroscopy has been used to study the conformations of somatostatin and some selected analogues in aqueous solution. The results indicate that the CS-SC dihedral angles of somatostatin and of these analogues (except Ala3,14-SS, which has no disulfide bond) are within 20 degrees of +/- 85 degrees, and the SS-CC dihedral angles are predominantly in the range of 50 degrees-180 degrees. Furthermore, from the behavior of the amide I' and amide III bands, it appears that somatostatin adopts a beta-pleated sheet structure, whereas its analogues are less ordered (to varying degrees)."
|
| 6113990 |
Rapid conversion of somatostatin to active metabolite in human plasma |
10.1016/0014-5793(81)80331-6. |
FEBS Lett |
Rapid conversion of somatostatin to active metabolite in human plasma
Abstract
|
| 6116194 |
A potent cyclic hexapeptide analogue of somatostatin |
10.1038/292055a0. |
Nature |
A potent cyclic hexapeptide analogue of somatostatin
Abstract
|
| 6120004 |
High-field 1H NMR studies of synthetic analogs of somatostatin. Structural features involving aromatic residues in an active eight-membered ring analog |
10.1016/0167-4838(82)90292-8. |
Biochim Biophys Acta |
High-field 1H NMR studies of synthetic analogs of somatostatin. Structural features involving aromatic residues in an active eight-membered ring analog
Abstract
- 360 MHz 1H-NMR data are presented for somatostatin and an analog whose primary structure is cyclo(-Gaba-Asn5-Phe6-Phe7-DTrp8-Lys9-Thr10-Phe11-). This report focuses on the aromatic portion of the spectrum, and this region for the analog is unambiguously assigned, using two experimental approaches: selective deuteration and photo-induced CIDNP. The most prominent feature of the analog aromatic spectrum is a two-proton resonance which exhibits a pronounced upfield shift. Significantly, this feature is also present for somatostatin and other active analogs (unpublished data). Assignments show that this resonance derives from the ortho hydrogens of the Phe6 and that aromatic resonances of Phe6 shift markedly upfield as temperature is decreased. In contrast, the aromatic resonances of Phe7,11 and DTrp8 reveal generally much smaller temperature coefficients and shift primarily downfield as temperature is decreased. Ring-current analysis shows that simple pair-wise parallel pi-stacking alone cannot give rise to the observed data. However, a simple hypothesis involving only two phenylalanine residues is totally consistent with the data if they maintain a time-averaged co-perpendicular orientation. Indirect evidence is offered which implicates only one phenylalanine stacking partner for Phe6, which we tentatively identify as Phe11.
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| 6122718 |
Characterization, regional distribution, and subcellular distribution of 125I-Tyr1-somatostatin binding sites in rat brain |
10.1111/j.1471-4159.1982.tb06627.x. |
J Neurochem |
Characterization, regional distribution, and subcellular distribution of 125I-Tyr1-somatostatin binding sites in rat brain
Abstract
|
| 6126352 |
Characterization of somatostatin receptors in the rat adrenal glomerulosa zone |
10.1210/endo-111-4-1376. |
Endocrinology |
Characterization of somatostatin receptors in the rat adrenal glomerulosa zone
Abstract
- Specific receptors for somatostatin have been identified and characterized in the rat adrenal glomerulosa zone in vivo and in vitro by binding studies with 125Iiodo-Tyr-somatostatin. In adult rats, the injection of 125Iiodo-Tyr-somatostatin was followed by rapid uptake of the labeled peptide in several tissues. The highest uptake was in the adrenal capsule, with a tissue to blood ratio of 4.5, followed by kidney, anterior pituitary, and liver with tissue to blood ratios of 2.0, 1.8, and 1.4, respectively. In vitro binding studies with adrenal capsular particles were performed at 16 C in the presence of bacitracin and thimerosal to reduce tracer degradation. Under these conditions, binding of 125Iiodo-Tyr-somatostatin to capsular membrane-rich fractions reached a steady state within 30-40 min and remained at a plateau for 120 min. Dissociation of bound somatostatin from its adrenal receptors was also rapid, with an initial half-time of 5 min. Equilibrium binding of somatostatin to adrenal capsular particles was saturable and of high affinity, with an association constant (Ka) of 1.5 x 10(10) M-1. The receptor-binding activities of several somatostatin analogs were consistent with their potencies as inhibitors of angiotensin II-stimulated aldosterone production in adrenal capsular cells and with their known biological activities upon GH release. These findings demonstrate that high affinity receptors with structural and biological specificities for somatostatin are present in the adrenal glomerulosa zone. Such receptors serve as the regulatory sites through which somatostatin inhibits the action of angiotensin II upon aldosterone production in the adrenal glomerulosa cell.
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