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P. R. Sowbna - One of the best experts on this subject based on the ideXlab platform.
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selectivity engineering in synthesis of 4 benzyloxy propiophenone using liquid liquid liquid phase transfer catalysis
Industrial & Engineering Chemistry Research, 2012Co-Authors: Ganapati D. Yadav, P. R. SowbnaAbstract:4-Benzyloxy propiophenone is an important active pharmaceutical intermediate (API) used in the production of drugs such as Ifenprodil (N-methyl-d-aspartate receptor antAgonist) and Buphenine (or nylidrin, a sympathomimetic and Beta-Adrenergic Agonist). The synthesis of this molecule involves cumbersome and highly polluting routes. In the current work, synthesis of 4-benzyloxy propiophenone was achieved by reacting benzyl chloride with 4-hydroxy propiophenone and sodium hydroxide in liquid–liquid–liquid (L-L-L) phase-transfer catalysis (PTC) with tetra butyl ammonium bromide (TBAB) as the catalyst. The novelty of the L-L-L PTC over L-L PTC is that the catalyst forms a separate phase and can be separated easily and reused several times. L-L-L PTC intensifies the rates of reaction and is 100% selective toward 4-benzyloxy propiophenone. Thus, the goal of green chemistry—waste minimization—was achieved. The effects of various parameters on the rate of reaction were studied. A mechanistic model was proposed to ...
Michel Bouvier - One of the best experts on this subject based on the ideXlab platform.
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a peptide derived from a β2 adrenergic receptor transmembrane domain inhibits both receptor dimerization and activation
Journal of Biological Chemistry, 1996Co-Authors: Terence E Hebert, Serge Moffett, Jeanpierre Morello, Thomas P Loisel, Daniel G Bichet, Cecile Barret, Michel BouvierAbstract:One of the assumptions of the mobile receptor hypothesis as it relates to G protein-coupled receptors is that the stoichiometry of receptor, G protein, and effector is 1:1:1 (Bourne, H. R., Sanders, D. A., and McCormick, F.(1990) Nature 348, 125-132). Many studies on the cooperativity of Agonist binding are incompatible with this notion and have suggested that both G proteins and their associated receptors can be oligomeric. However, a clear physical demonstration that G protein-coupled receptors can indeed interact as dimers and that such interactions may have functional consequences was lacking. Here, using differential epitope tagging we demonstrate that beta2-adrenergic receptors do form SDS-resistant homodimers and that transmembrane domain VI of the receptor may represent part of an interface for receptor dimerization. The functional importance of dimerization is supported by the observation that a peptide derived from this domain that inhibits dimerization also inhibits Beta-Adrenergic Agonist-promoted stimulation of adenylyl cyclase activity. Moreover, Agonist stimulation was found to stabilize the dimeric state of the receptor, while inverse Agonists favored the monomeric species, which suggests that interconversion between monomeric and dimeric forms may be important for biological activity.
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Agonist modulated palmitoylation of beta 2 adrenergic receptor in sf9 cells
Journal of Biological Chemistry, 1992Co-Authors: Bernard Mouillac, Michael Dennis, M Caron, Helene Bonin, Michel BouvierAbstract:The palmitoylation of the human beta 2-adrenergic receptor (beta 2-AR) was studied in recombinant baculovirus-infected insect Sf9 cells. At 48 h post-infection, a high level expression of an epitope-tagged beta 2-AR (10-25 pmol/mg protein) was detected by [125I]iodocyanopindolol ([125I]CYP) binding assays. The identity of the receptor was confirmed both by photoaffinity labeling and immunoblotting. The fusion receptor displayed typical beta 2-AR pharmacological properties and conferred a Beta-Adrenergic sensitive adenylyl cyclase activity to the Sf9 cells. Moreover, exposure of the Sf9 cells to the Beta-Adrenergic Agonist isoproterenol induced a rapid desensitization of the receptor-stimulated adenylyl cyclase activity. Purification of the epitope-tagged beta 2-AR by immunoprecipitation as well as by alprenolol-Sepharose affinity chromatography revealed that the receptor is covalently modified with palmitic acid in the insect cells as is observed in mammalian cells. In addition, short-term incubation of the cells with isoproterenol led to a specific increase in the incorporation of [3H]palmitate in the receptor, consistent with a rapid Agonist-modulated turnover of the beta 2-AR-attached palmitic acid. These results suggest that Agonist-mediated regulation of beta 2-AR post-translational palmitoylation could represent an other regulatory process for G protein-coupled receptors.
Ganapati D. Yadav - One of the best experts on this subject based on the ideXlab platform.
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selectivity engineering in synthesis of 4 benzyloxy propiophenone using liquid liquid liquid phase transfer catalysis
Industrial & Engineering Chemistry Research, 2012Co-Authors: Ganapati D. Yadav, P. R. SowbnaAbstract:4-Benzyloxy propiophenone is an important active pharmaceutical intermediate (API) used in the production of drugs such as Ifenprodil (N-methyl-d-aspartate receptor antAgonist) and Buphenine (or nylidrin, a sympathomimetic and Beta-Adrenergic Agonist). The synthesis of this molecule involves cumbersome and highly polluting routes. In the current work, synthesis of 4-benzyloxy propiophenone was achieved by reacting benzyl chloride with 4-hydroxy propiophenone and sodium hydroxide in liquid–liquid–liquid (L-L-L) phase-transfer catalysis (PTC) with tetra butyl ammonium bromide (TBAB) as the catalyst. The novelty of the L-L-L PTC over L-L PTC is that the catalyst forms a separate phase and can be separated easily and reused several times. L-L-L PTC intensifies the rates of reaction and is 100% selective toward 4-benzyloxy propiophenone. Thus, the goal of green chemistry—waste minimization—was achieved. The effects of various parameters on the rate of reaction were studied. A mechanistic model was proposed to ...
P J Conn - One of the best experts on this subject based on the ideXlab platform.
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presynaptic enhancement of excitatory synaptic transmission by beta adrenergic receptor activation
Journal of Neurophysiology, 1994Co-Authors: Robert W Gereau, P J ConnAbstract:1. Previous studies have shown that Beta-Adrenergic receptor activation has many effects on neuronal function in hippocampal area CA1. However, all of the physiological effects of Beta-Adrenergic receptor activation in this region reported to date have been attributed to postsynaptic mechanisms. A series of studies was performed to test the hypothesis that Beta-Adrenergic receptor activation also acts presynaptically to enhance excitatory synaptic transmission. 2. Application of the selective Beta-Adrenergic Agonist isoproterenol to hippocampal slices induced an increase in the amplitude of evoked excitatory postsynaptic currents (EPSCs) in CA1 pyramidal cells. This response was potentiated in the presence of a cyclic nucleotide phosphodiesterase inhibitor. Isoproterenol also resulted in the appearance of a late inward synaptic current that likely represents polysynaptically evoked EPSCs. Both the increased amplitude of the monosynaptic EPSC and the appearance of polysynaptic EPSCs in response to isoproterenol were blocked by H89, an inhibitor of adenosine 3',5'-cyclic monophosphate (cAMP)-dependent protein kinase. 3. Isoproterenol induced an increase in the frequency of spontaneous miniature EPSCs but did not affect the amplitude of these currents. In addition, isoproterenol had no effect on currents elicited by direct application of the ionotropic glutamate receptor Agonist, (R,S)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA). 4. These results suggest that activation of presynaptic Beta-Adrenergic receptors enhances synaptic transmission in area CA1 via activation of cAMP-dependent protein kinase.
Mohammad Koohmaraie - One of the best experts on this subject based on the ideXlab platform.
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effects of a beta adrenergic Agonist l 644 969 and male sex condition on muscle growth and meat quality of callipyge lambs
Journal of Animal Science, 1996Co-Authors: Mohammad Koohmaraie, S D Shackelford, T L WheelerAbstract:The objective of this study was to determine the effects of dietary administration of a Beta-Adrenergic Agonist (BAA; L-644,969) and male sex condition (ram vs wether) on muscle growth and meat quality of Dorset x Romonov lambs believed to be heterozygous for the callipyge gene. At approximately 17 wk of age, lambs were blocked by weight within each sex condition and randomly assigned to BAA treatment group. The interaction of BAA and male sex condition was not significant for any of the traits measured. Rams had greater initial and final live weights, average daily gain, and hot carcass weight (P .05) from wethers with respect to any of the carcass traits, possibly because the wethers were so lean and heavily-muscled that there was little room for improvement. Kidney-pelvic fat weight was reduced 26% by BAA (P .05) by BAA or male sex condition. Administration of BAA increased calpastatin activity at 20 d (1.1 vs 1.5 units/g), but not at 0 h (3.9 vs 4.8 units/g) postmortem, decreased myofibril fragmentation index (60.7 vs 44.9), and increased shear force (8.2 vs 10.9 kg) at 20 d postmortem (P < .05). These data suggest that muscle growth rates are near maximum in lambs expressing the callipyge gene, regardless of male sex condition or BAA treatment. Therefore, it seems that the callipyge gene exerts most, but not all, of its effect through intracellular events similar to those initiated by administering BAA.
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bovine skeletal muscle calpastatin cloning sequence analysis and steady state mrna expression
Journal of Animal Science, 1994Co-Authors: John Killefer, Mohammad KoohmaraieAbstract:: Calpastatin is a specific inhibitor of the calpains. Calpains play a key role in postmortem tenderization of meat and have been hypothesized to be involved in muscle protein degradation in living tissue. Isolation, cloning of complementary DNA, and nucleotide sequencing of bovine calpastatin from the longissimus muscle have been completed. Two clones were identified that encompass the entire coding sequence. Clone pCR41, derived by reverse transcription-PCR, covers domains L and 1; clone pBSA1, obtained from cDNA library screening, covers domains 2 through 4 in addition to the 3'-nontranslated region. Nucleotide sequence analysis of the cDNA for bovine calpastatin revealed an average nucleotide sequence identity of approximately 70 to 80% compared with published calpastatin nucleotide sequences of human, rabbit, and pig. Exon 3, corresponding to a highly conserved 22-amino acid region, was deleted from bovine calpastatin domain L. The calculated molecular weight of bovine skeletal muscle calpastatin of 706 amino acid residues (M(r) 75,842) corresponds to the value of purified bovine skeletal muscle calpastatin as determined by SDS-PAGE (M(r) 68,000). Northern blot analysis revealed the presence of multiple calpastatin mRNA transcripts having estimated sizes of 3.8, 3.0, and 1.5 kb in beef and 3.8, 3.0, 2.5, and 1.5 kb in sheep. Calpastatin mRNA expression was increased with Beta-Adrenergic Agonist-induced muscle hypertrophy.