Search results for "Cysteamine"
showing 10 items of 12 documents
Field desorption mass spectrometric characterization of thiol conjugates related to the oxidative metabolism of the anticancer drug 4′-(9-acridinylam…
1983
Conjugation products with glutathione (GSH) and other endogenous thiol derivatives related to the oxidative metabolism of the anticancer drug, 4′-(9-acridinlyamino) methanesulfon-m-anisidide (m-AMSA) were synthesized and characterized by field desorption mass spectrometry. The primary microsomal oxidation product of m-AMSA, m-AQDI, was prepared by MnO2 oxidation of the parent drug and reacted with equimolar GSH, cysteine, N-acetylcysteine and N-acetylcysteine methyl ester to form m-AMSA-(5′)-thiol conjugates linkedat the aniline ring, as major products. Field desorption mass spectra of the conjugates provided abundant [MH]plus; ions, and characteristic fragment ions by cleavage at the thioe…
Bile acid–cysteamine conjugates: Structural properties, gelation, and toxicity evaluation
2011
Abstract Design, synthesis, and characterization of six novel bile acid–cysteamine conjugates together with investigation of their structural studies, gelation properties, and preliminary toxicity evaluation, are reported. Solid state properties of selected compounds were studied by means of X-ray diffraction and 13C CPMAS NMR spectroscopy. N-(2-thioethyl)-3α,7α,12α-trihydroxy-5β-cholan-24-amide was shown to exhibit (pseudo)polymorphism, and a single crystal structure of its non-stoichiometric hydrate is reported herein. Cholyl and dehydrocholyl derivatives bearing three functionalities in their steroidal backbone were shown to undergo self-assembly leading to gelation in certain organic so…
Inhalable nano into micro dry powders for ivacaftor delivery: The role of mannitol and cysteamine as mucus-active agents.
2020
In this paper the innovative approach of Nano into micro (NiM9 was developed to produce Nanoparticles loaded Ivacaftor to incorporate into mannitol or mannitol/cysteamine micromatrices for drug pulmonary administration in CF. Nanoparticles composed by a mixture of two polyhydrohydroxyethtylaspartamide copolymers containing a loading of Ivacaftor of 15.5 % w/w were produced. These Nanoparticles were incorporated into microparticles to obtain NiM that were characterized in terms of size and size distribution, interaction with CF-AM by rheological and turbidimetric studies as well as by aerodynamic diameter measurements. Finally the activity of Ivacaftor into these NiM was evaluated by in vitr…
The Effects of Sulphydryl Reagents on the Binding and Mixed Function Oxidation of Hexobarbital in Rat Hepatic Microsomes
1975
1. The effects of the sulphydryl reagents p-chloromercuribenzoate, N-ethylmaleimide and iodoacetamide on the binding spectrum, oxygen consumption and formation of a suspected substrate-cytochrome P-450-oxygen complex for hexobarbital in rat liver microsomes were investigated. 2. The oxygen consumption caused by hexobarbital oxidation was inhibited non-competitively by all three agents, with 50% inhibition at 4 times 10(-5) M for p-chloromercuribenzoate, 3-7 times 10(-4) M for N-ethylmaleimide and 1-9 times 10(-3) M for iodoacetamide. Cysteamine protected and at least partially reversed this inhibition. 3. p-chloromercuribenzoate inhibited the formation of the cytochrome P-450-substrate-oxyg…
Synthesis of and structural studies on lead(II) cysteamin complexes.
2004
The novel compounds PbCl(2).(SCH(2)CH(2)NH(3)) (1), Pb(SCH(2)CH(2)NH(2))(2).2PbCl(SCH(2)CH(2)NH(2)) (2), and Pb(SCH(2)CH(2)NH(2))(2) (3) were synthesized by reaction of PbO or PbCl(2) with [HSCH(2)CH(2)NH(3)]Cl and NaOH, and were characterized by elemental analysis, IR-, and UV/vis-spectroscopy. Single-crystal X-ray diffraction revealed different coordination modes for the two Pb atoms in 2. The Pb atom in the Pb(SCH(2)CH(2)NH(2))(2) unit forms two covalent Pb-S and two intramolecular dative Pb...N bonds, leading to a pseudo trigonal bipyramidal configuration with a stereochemically active lone pair. The Pb atom in the PbCl(SCH(2)CH(2)NH(2)) unit, the first moiety structurally characterized…
Redox regulation of enzymatic activity and proteolytic susceptibility of ribulose-1,5-bisphosphate carboxylase/oxygenase fromEuglena gracilis.
1992
The activity of ribulose-1,5-bisphosphate carboxylase/oxygenase fromEuglena gracilis decays steadily when exposed to agents that induce oxidative modification of cysteine residues (Cu(2+), benzofuroxan, disulfides, arsenite, oxidized ascorbate). Inactivation takes place with a concomitant loss of cysteine sulfhydryl groups and dimerization of large subunits of the enzyme. 40% activity loss induced by the vicinal thiol-reagent arsenite is caused by modification of a few neighbor residues while the almost complete inactivation achieved with disulfides is due to extensive oxidation leading to formation of mixed disulfides with critical cysteines of the protein. In most cases oxidative inactiva…
Electrochemical impedance spectroscopy of polyelectrolyte multilayer modified gold electrodes: influence of supporting electrolyte and temperature.
2005
Electrochemical impedance spectroscopy and cyclic voltammetry are employed to characterize poly(styrenesulfonate)/poly(allylamine hydrochloride) multilayers assembled onto cysteamine-modified gold surfaces. The influence of the supporting electrolyte and temperature on the impedance response is studied because of both its practical interest and the need to test further the capillary membrane model recently developed by Barreira et al. [J. Phys. Chem. B 2004, 108, 17973]. The results obtained are interpreted quite satisfactorily in terms of this model, thus providing additional support to its usefulness for the description of ionic transport through polyelectrolyte multilayers. It is observe…
The Influence of Thiol Reagents on the Isoenzyme Pattern of Plant L+Lactate Dehydrogenase (EC 1.1.1.27)
1978
Summary Lactate dehydrogenase from potato tubers was incubated together with various thiol reagents and the effect on the electrophoretic behavior of its isoenzymes studied. while disulfides, alkylating agents, and H202 did not alter the number and electrophoretic behavior of the isoenzymes of L + LDH, reduced glutathione and 2-mercaptoethanol led to an increase in the number of isoenzymes. The reaction was dependent on concentration and pH. On the other hand, cysteine and cysteamine had no such effect. Results are discussed in view of the possible secondary nature of the plant LDH isoenzymes.
Effect of potential antidotes on the acute toxicity of acrylonitrile
1981
Rats were intoxicated with lethal doses of acrylonitrile by different routes of application, and the effect of potential antidotes was studied. The cyanide antidotes 4-dimethylaminophenol plus thiosulfate showed some protective effect only after oral but not after i.p. or inhalatory acrylonitrile application. Of the sulfhydryl compounds cysteine, N-acetylcysteine, cysteamine and diethyldithiocarbamate the two antidotes cysteine and, to some lesser extent, N-acetylcysteine proved especially effective. Cysteine, at a dose of 200 mg/kg (i.p.), prevented the lethal effect of 100 mg/kg acrylonitrile (i.p.) even when given 2 h after the acrylonitrile dose. From these experiments a tentative sched…
Cysteamine and its homoleptic complexes with group 12 metal ions. Differences in the coordination chemistry of ZnII, CdII, and HgII with a small N,S-…
2005
2-Ammoniumethanethiolate, (-)SCH(2)CH(2)NH(3)(+), the first structurally characterized zwitterionic ammoniumthiolate, is the stable form of cysteamine (HL) in the solid state and in aqueous solution. Reactions of ZnCl(2), Cd(Oac)(2), and HgCl(2) with cysteamine and NaOH in a 1:2:2 ratio, respectively, lead to the homoleptic complexes ML(2). Their single-crystal X-ray structures demonstrate basic differences in the coordination chemistry of Zn(II), Cd(II), and Hg(II). While chelating N,S-coordination modes are found for all metal ions, Zn(II) forms a mononuclear complex with a distorted tetrahedral Zn(N(2)S(2)) coordination mode, whereas Hg(II) displays a dimer with Hg(N(2)S(2)) coordinated …