Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:4.6.1.1 (adenylate cyclase)
19,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The 2-nitro-4-azidophenyl(NAP)-D-Ala2-Leu5-Enkephalin derivatives: Try-D-Ala-Gly-Phe-Leu CONCH2CH2NH-NAP (E-NAP-EDA) and Try-D-Ala-Gly-Phe-Leu CONCH2CH2NH-COCH2CH2NHNAP(E-NAP- -Ala-EDA) were synthesized by conventional peptide methods. Their structure was determined by amino acid analysis, ultra violet, visible and infra red spectroscopy. Both peptides were shown a) to bind with high affinity to the opiate receptors of rat brain membranes and b) to inhibit strongly the contractions of electrically stimulated vas deferens and the adenyl cyclase of the NG 108-15 cell membranes. These effects were reversed by the antagonist naloxone. Photoloysis of the rat brain membranes-(E-NAP- -Ala-EDA) complex caused a 20-30% inactivation of the opiate receptors. Inactivation was prevented when the complex was irradiated in the presence of naloxone. The radio-labeled derivatives of these enkephalin analogs may prove useful photochemical labels of the opiate receptor.
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PMID:Photolabile ligands for opiate receptors. 629 69

Exorphins, peptides with opioid activity, have previously been isolated from pepsin hydrolysates of alpha-casein [Zioudrou, C., Streaty, R. A., & Klee, W. A. (1979) J. Biol. Chem. 254, 2446-2449]. Analysis of these peptides shows that they correspond to the sequences 90-96, Arg-Tyr-Leu-Gly-Tyr-Leu-Glu, and 90-95, Arg-Tyr-Leu-Gly-Tyr-Leu, of alpha-casein. These peptides, as well as two of their analogues Tyr-Leu-Gly-Tyr-Leu-Glu (91-96) and Tyr-Leu-Gly-Tyr-Leu (91-95), have now been synthesized and characterized. Their opioid activity was examined by three different bioassays: (a) displacement of D-2-alanyl[tyrosyl-3,5-3H]enkephalin-(5-L-methioninamide) and [3H]dihydromorphine from rat brain membranes; (b) naloxone-reversible inhibition of adenylate cyclase in homogenates of neuroblastoma x glioma hybrid cells; (c) naloxone-reversible inhibition of electrically stimulated contractions of the mouse vas deferens. The synthetic peptide of sequence 90-96 was the most potent opioid in all three bioassays and its potency was similar to that of the isolated alpha-casein exorphins. The synthetic peptides were totally resistant to hydrolysis by trypsin and homogenates of rat brain membranes, but were partially inactivated by chymotrypsin and subtilisin. The difference in opioid activity of alpha-casein exorphins may be related to differences in conformational flexibility observed by NMR spectroscopy.
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PMID:Opioid activities and structures of alpha-casein-derived exorphins. 631 43

The interaction of platelets with collagen involves short aminoacid sequences which recur along the fibres. Platelet aggregation by collagen and serotonin release is inhibited by a synthetic octapeptide LYS-PRO-GLY-GLU- PRO-GLY-PRO-LYS- derived from type III collagen. In contrast, this octapeptide inhibits only weakly the retention of platelets labelled with 111Indium to collagen, suggesting that it has a limited effect on platelet adhesion. Preincubation of the octapeptide with platelets inhibits the rise of cAMP level caused by activating adenylate cyclase by various concentrations of PGI2. The octapeptide at 5 mM reverses the inhibition by PGI2 of the adhesion of platelets to collagen. These results suggest that the octapeptide affects the intrinsic activity (manifested as platelet aggregation and secretion) more than the recognition of collagen by its receptor (manifested by adhesion).
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PMID:Effect of a collagen derived octapeptide on different steps of the platelet/collagen interaction. 632 Apr 90

The effects of FMRFamide (Phe-Met-Arg-Phe-NH2), YGG-FMRFamide (Tyr-Gly-Gly-Phe-Met-Arg-Phe-NH2), and Met-enkephalin (Tyr-Gly-Gly-Phe-Met) on the isolated Aplysia anterior gizzard were examined. (i) FMRFamide inhibits spontaneous gut activity. While YGG-FMRFamide also inhibits spontaneous activity it is less potent than FMRFamide. Met-enkephalin does not affect spontaneous gut activity. (ii) FMRFamide inhibits the excitatory response of acetylcholine on both the anterior gizzard of Aplysia and the isolated stomach region of Navanax. (iii) Neither FMRFamide, YGG-FMRFamide, Met-enkephalin, nor acetylcholine stimulated the activity of adenylate cyclase in the Aplysia anterior gizzard.
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PMID:FMRFamide effects on spontaneous and induced contractions of the anterior gizzard in Aplysia. 662 35

The ORL1 receptor, an orphan receptor whose human and murine complementary DNAs have recently been characterized, structurally resembles opioid receptors and is negatively coupled with adenylate cyclase. ORL1 transcripts are particularly abundant in the central nervous system. Here we report the isolation, on the basis of its ability to inhibit the cyclase in a stable recombinant CHO(ORL1+) cell line, of a neuropeptide that resembles dynorphin A9 and whose amino acid sequence is Phe-Gly-Gly-Phe-Thr-Gly-Ala-Arg-Lys-Ser-Ala-Arg-Lys-Leu-Ala-Asn-Gln. The rat-brain cDNA encodes the peptide flanked by Lys-Arg proteolytic cleavage motifs. The synthetic heptadecapeptide potently inhibits adenylate cyclase in CHO(ORL1+) cells in culture and induces hyperalgesia when administered intracerebroventricularly to mice. Taken together, these data indicate that the newly discovered heptadecapeptide is an endogenous agonist of the ORL1 receptor and that it may be endowed with pro-nociceptive properties.
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PMID:Isolation and structure of the endogenous agonist of opioid receptor-like ORL1 receptor. 756 39

The octapeptide Gly-Lys-Val-Leu-Lys-Lys-Arg-Arg (termed leukocorticotropin, LCT) corresponding to the ACTH-like sequence 81-88 of human pro-interleukin-1 alpha and its derivative Tyr-Gly-Lys-Val-Leu-Lys-Lys-Arg-Arg were synthesized. The 125I-labeled Tyr-LCT specifically interacts with one type of receptor on the surface of murine splenocytes (Kd = (1.45 +/- 0.04) x 10(-8) M, the number of binding sites is equal to 4500) and with two types of receptors on the surface of murine peritoneal macrophages (Kd1 = (5.9 +/- 1.0) x 10(-9) M and Kd2 = (2.6 +/- 2.2) x 10(-7) M). LCT and Tyr-LCT significantly increase the adenylate cyclase activity of murine peritoneal macrophages. The receptor binding and adenylate cyclase stimulation activity of LCT and Tyr-LCT are inhibited by ACTH (13-24).
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PMID:Receptor-binding properties of the peptides corresponding to the ACTH-like sequence of human pro-interleukin-1 alpha. 759 Sep 7

A novel myotropic heptapeptide was isolated from an extract of 54,000 heads of adult Leptinotarsa decemlineata by means of high performance liquid chromatography (HPLC), using the Locusta migratoria oviduct motility bioassay as monitoring system. The full primary structure was established as H-Ala-Tyr-Asn-Gly-Pro-Leu-Ala-NH2. This peptide, designated as Led-MNP-I, has a unique structure and does not belong to any known vertebrate or invertebrate peptide family. Two adjacent Led-MNP-I-immunoreactive perikarya were found in each optic lobe and in each half of all thoracic ganglia. Its absence from the pars intercerebralis and neurohemal organs suggests that Led-MNP-I is not a neurohormone but a neurotransmitter or neuromodulator. Treatment of isolated oviducts with varying concentrations of Led-MNP-I did not elicit significant changes in the level of cAMP concentration, suggesting that cAMP does not act as a second messenger for Led-MNP-I. Instead, Led-MNP-I induces an elevation of IP3. Treatment with Led-MNP-I did not stimulate cAMP production in the Colorado beetle brain, but this could be due to the very small number of receptive cells present. Both tissues contained a forskolin-sensitive adenylate cyclase enzyme.
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PMID:Identification, characterization, and immunological localization of a novel myotropic neuropeptide in the Colorado potato beetle, Leptinotarsa decemlineata. 765 86

We previously reported that kappa opioids stimulated the release of human placental lactogen (hPL) from trophoblastic cells and that this effect was prevented by co-incubation with naloxone. We also reported that adenylate cyclase was not directly involved in this process. In order to understand the post-receptor events mediating hPL release by opioids in the human placenta, we studied the role of extracellular calcium. Human trophoblastic cells obtained by trypsin digestion were cultured for 48 h in Ham's F-10 medium supplemented with 10% fetal bovine serum (FBS), 200 U/ml penicillin, and 200 micrograms/ml streptomycin. 45Ca2+ influx was then measured by filtration on glass-fiber filters. We observed a time- and dose-dependent stimulation of 45Ca2+ influx by ethylketocyclazocine (EKC) with an EC50 of 0.5 nM and a maximal stimulation of 196% over control. This effect was completely blocked by naloxone, a non-specific opioid antagonist, and by nor-binaltorphimine, a specific kappa antagonist. We also demonstrated that U-50,488 (kappa agonist) had the same stimulatory effect as EKC (221 +/- 25% of control). D-Ala2,NMe-Phe4,Gly-ol5)-enkephalin (DAGO) (mu agonist) slightly stimulated Ca2+ influx (128 +/- 5% of control, p > 0.05) whereas D-Ser2,Leu,Thr6)-enkephalin (DSLET) (delta agonist) had no effect. Pre-incubation of trophoblastic cells with pertussis toxin (PTX) did not affect the EKC-induced 45Ca2+ influx, suggesting that this placental opiate effect is not coupled with PTX-sensitive G proteins.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The modulation of placental lactogen release by opioids: a role for extracellular calcium. 768 40

The action of Gly-Tyr-NH2, (GY-NH2) and Gly-Tyr-LYS(GYK) on 125I-LH binding, cAMP accumulation and progesterone production was investigated. Incubation of rat luteal cells for 2.5 h with GY-NH2 and GYK at dosage of 0.2 mmol/L caused a significant inhibition of basal and gonadotropin-stimulated steroidogenesis. GY-NH2 and GYK were also found to reduce cAMP formation in response to hCG. The activity of adenylate cyclase of luteal cells was inhibited by 0.2 mmol/LGY-NH2 and GYK. GY-NH2 and GYK at a concentration of 0.2 mmol/L were not found to have an inhibitory effect on 8Br-cAMP-stimulated progesterone production. GY-NH2 and GYK did not affect 125I-LH binding to LH receptors on the luteal cell surface. These results suggest that GY-NH2 and GYK inhibit steroidogenesis at the step of gonadotropin-stimulated cAMP formation in luteal cells. Adenylate cyclase in luteal cells was also inhibited.
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PMID:Study on the mechanism and effects of Gly-Tyr-NH2 and Gly-Tyr-Lys on rat luteal cells in vitro. 771 62

To investigate roles of second extracellular loop sequences in peptide and nonpeptide ligand recognition by human opiate receptors, we have constructed a chimeric receptor in which this domain of the human mu opiate receptor has been replaced with that of the human kappa opiate receptor. The chimeric opiate receptor displays dramatically increased affinity for dynorphin peptides. Affinities for dynorphin A-(1-17), dynorphin A-(1-13), and alpha-neoendorphin increase by up to 250-fold when compared with the wild-type human mu opiate receptor. The chimera maintains recognition of the mu-selective ligands morphine and [D-Ala2,MePhe4,Gly-ol5]enkephalin and displays no significant changes in affinity for the kappa-selective small molecule ligand U50,488. The chimeric opiate receptor displays evidence for effective G-protein coupling; 100 nM dynorphin A-(1-17) is as effective as 100 nM morphine at inhibiting forskolin-stimulated adenyl cyclase activity through actions at the chimeric receptor. These data suggest that the putative second extracellular loop contributes substantially to the kappa receptor's selectivity in dynorphin ligand recognition.
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PMID:Human kappa opiate receptor second extracellular loop elevates dynorphin's affinity for human mu/kappa chimeras. 792 6


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