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Cyclase

About: Cyclase is a research topic. Over the lifetime, 10162 publications have been published within this topic receiving 388566 citations.


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Journal ArticleDOI
TL;DR: GTP, in addition to its effects on glucagon action, stimulates the rate of dissociation of glucagon from its receptor and, as a consequence, causes a decrease in the steady state levels of bound glucagon.

225 citations

Journal ArticleDOI
TL;DR: Neuropeptides of the adipokinetic hormone (AKH) family regulate inter alia mobilisation of various substrates from stores in the fat body of insects during episodes of flight.

225 citations

Journal ArticleDOI
TL;DR: This work believes that it has purified a guanine nucleotide- and Mg2+-binding inhibitory regulatory component of adenylyl cyclases--i.e., the Ni.
Abstract: The final step in a scheme for the purification of the guanine nucleotide- and Mg2+-binding stimulatory regulatory component (Ns) of adenylyl cyclase [adenylate cyclase; ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] from human erythrocyte membranes involves chromatography over hydroxylapatite (HAP) which yields two fractions. The first fraction (HAP I) contains predominantly two peptides that, upon sodium dodecyl sulfate/polyacrylamide gel electrophoresis, migrate with Mr values of 39,000 and 35,000. The second fraction (HAP II) contains predominantly Ns formed of two peptides of Mr 42,000 and 35,000. The HAP I, Mr 39,000 peptide is shown to be a substrate for the ADP-ribosylating toxin of Bordetella pertussis (pertussis toxin). Upon sucrose density gradient centrifugation, both the Mr 39,000 and the Mr 35,000 peptides of HAP I migrate at about 4 S. Treatment of HAP I with guanine nucleotide and Mg2+ prior to centrifugation results in a coordinated change in the migration of both peptides to 2 S. It is postulated that HAP I contains an alpha beta heterodimeric protein composed of an alpha subunit of Mr 39,000 and a beta subunit of Mr 35,000. Further, this protein dissociates under the influence of guanine nucleotides and Mg2+ into its individual alpha and beta subunits. Because previous studies have shown that treatment of cells and cell membranes with pertussis toxin results in attenuation of the effects of hormones that inhibit adenylyl cyclase activity, and because this effect correlates with the ADP-ribosylation of a Mr approximately equal to 40,000 peptide, we believe that we have purified a guanine nucleotide- and Mg2+-binding inhibitory regulatory component of adenylyl cyclases--i.e., the Ni.

224 citations

Journal ArticleDOI
TL;DR: The monophasic slope of dose/effect curves on both parameters suggested interaction with one class of PACAP receptor, and receptors coupled to adenylate cyclase were, in general, more sensitive to PACAP(1-38) analogs than to the corresponding PACAP-1-27 analogs.
Abstract: In these structure activity studies, the 46 analogs of the 27-amino-acid form of the pituitary-adenylate-cyclase-activating peptide, PACAP(1-27), and the 38-amino-acid form, PACAP(1-38), were either monosubstituted or bisubstituted at positions 1-3, 20 and 21 or N-terminally shortened. All analogs were compared on human neuroblastoma NB-OK-1 cell membranes for their ability to occupy 125I-[AcHis1]PACAP(1-27)-labelled receptors (AcHis, N alpha-acetylhistidine) and to activate adenylate cyclase (in terms of potency and intrinsic activity). The monophasic slope of dose/effect curves on both parameters suggested interaction with one class of PACAP receptor. Residues 28-38 in the C-terminally extended peptide, PACAP(1-38), played a favorable role in recognition, in that receptors coupled to adenylate cyclase were, in general, more sensitive to PACAP(1-38) analogs than to the corresponding PACAP(1-27) analogs. At variance with PACAP(6-27), PACAP(6-38) was well recognized and acted as a potent competitive antagonist (Ki 1.5 nM). Residues 1-3 were all important in enzyme activation: modification of the beta-turn potential gave full agonists (the LAla2 and DAla2 derivatives) or partial agonists (LPhe2 and DPhe2; LArg2 and DArg2; Glu3 and Asn3). Finally, a proper alpha-helix was also important: the combined substitution of Lys21/Lys22 by Gly21/Gly22 decreased the binding affinity sharply.

224 citations

Journal ArticleDOI
TL;DR: The novel enzymatic activity and stress resistance together point toward a role for YybT in stress signaling and response.

224 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202324
202257
202145
202048
201939
201856