Topic
Cyclase
About: Cyclase is a research topic. Over the lifetime, 10162 publications have been published within this topic receiving 388566 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: Evidence is presented that suggests intracellular Ca2+ sequestration is the mechanism involved in β-adrenergically mediated relaxation of smooth muscle and quite a different mechanism is implied by involving the Na+–K2+ pump and Na–Ca2+ exchange carrier.
Abstract: Various mechanisms have been proposed for β-adrenergically mediated relaxation of smooth muscle. All theories suggest the involvement of cyclic AMP as a second messenger: β-agonists stimulate adenylate cyclase which converts ATP to cyclic AMP1 and protein kinase, activated by cyclic AMP, is then thought to catalyse a protein phosphorylation that leads to a reduction in free Ca2+, thus effecting relaxation1. How this last step is accomplished is much debated, but the following possibilities are currently considered as the mechanisms responsible for cyclic AMP-induced reduction of cytoplasmic Ca2+: activation of a Ca2+-ATPase in the plasma and/or sarcoplasmic reticulum membranes which lowers cytoplasmic [Ca2+] in a direct manner or stimulation of (Na+–K+)ATPase in the cell membrane which may indirectly effect Ca2+ extrusion2–8. Among the hypotheses suggested, those of Ca2+ sequestration by the sarcoplasmic reticulum and of Ca2+ extrusion across the cell membrane are consistent with each other if it is assumed that both processes are effected by a cyclic AMP-sensitive Ca2+-ATPase. However, quite a different mechanism is implied by involving the Na+–K2+ pump and Na+–Ca2+ exchange carrier. In this report, we present evidence that suggests intracellular Ca2+ sequestration is the mechanism involved.
144 citations
TL;DR: Results indicate that the fungus has a bifunctional diterpene cyclase that can convert geranylgeranyl diphosphate into ent-kaurene and may be separate catalytic sites for the two cyclization reactions.
144 citations
TL;DR: The structure of ent-copalyl diphosphate synthase (CPS) reveals three α-helical domains (α, β, γ), as also observed in the related diterpene cyclase taxadiene synthase, but active sites are located at the interface of the βγ domains in CPS but exclusively in the α domain of taxadienes synthase.
Abstract: The structure of ent-copalyl diphosphate synthase reveals three α-helical domains (α, β and γ), as also observed in the related diterpene cyclase taxadiene synthase. However, active sites are located at the interface of the βγ domains in ent-copalyl diphosphate synthase but exclusively in the α domain of taxadiene synthase. Modular domain architecture in plant diterpene cyclases enables the evolution of alternative active sites and chemical strategies for catalyzing isoprenoid cyclization reactions.
143 citations
TL;DR: The analysis of the CD38 substrate binding models revealed two key residues that may be critical in controlling CD38's multifunctionality of NAD hydrolysis, ADP-ribosyl cyclase, and cADPR hydrolytic activities.
143 citations
TL;DR: CAMP Phosphodiesterase, Adenyl Cyclase, and Release of cAMP.PROKARYOTES .
Abstract: PROKARYOTES . Cellular Pools of cAMP and Release of cAMP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362 Adenyl Cyclase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363 cAMP Phosphodiesterase. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364
143 citations