Search results for "Cystamine"
showing 9 items of 9 documents
The Candida albicans ENO1 gene encodes a transglutaminase involved in growth, cell division, morphogenesis, and osmotic protection
2018
Candida albicans is an opportunistic fungus that is part of the normal microflora commonly found in the human digestive tract and the normal mucosa or skin of healthy individuals. However, in immunocompromised individuals, it becomes a serious health concern and a threat to their lives and is ranked as the leading fungal infection in humans worldwide. As existing treatments for this infection are non-specific or under threat of developing resistance, there is a dire necessity to find new targets for designing specific drugs to defeat this fungus. Some authors reported the presence of the transglutaminase activity in Candida and Saccharomyces, but its identity remains unknown. We report here…
Development and in vitro Evaluation of Antigen-Loaded Poly(amidoamine) Nanoparticles for Respiratory Epithelium Applications
2013
A poly(amidoamine) with disulfide linkages in the main chain and 4-hydroxybutyl and ω-carboxy-PEG groups (9:1 ratio) as side chains was prepared by Michael addition polymerization of cystamine bisacrylamide with 4-hydroxybutylamine and ω-carboxy-PEG-amine. To develop therapeutic protein formulations for improved delivery of antigen via the intranasal route, nanoparticles were prepared from this polymer by self-assembly with p24 or ovalbumin as the model proteins and CpG as the adjuvant. The nanoparticles incorporated the antigens and adjuvant from the feed solution with high efficiency (∼90 %) and have sizes of 112 and 169 nm, respectively, with low positive surface charge (∼+2 mV). Formula…
Involvement of transglutaminase in the formation of covalent cross-links in the cell wall of Candida albicans.
1995
Activity of the enzyme glutaminyl-peptide--glutamylyl-transferase (EC 2.3.2.13; transglutaminase), which forms the interpeptidic cross-link N epsilon-(gamma-glutamic)-lysine, was demonstrated in cell-free extracts obtained from both the yeast like and mycelial forms of Candida albicans. Higher levels of enzymatic activity were observed in the cell wall fraction, whereas the cytosol contained only trace amounts of activity. Cystamine, a highly specific inhibitor of the enzyme, was used to analyze a possible role of transglutaminase in the organization of the cell wall structure of the fungus. Cystamine delayed protoplast regeneration and inhibited the yeast-to-mycelium transition and the inc…
Transglutaminase activity is involved in Saccharomyces cerevisiae wall construction
2002
Transglutaminase activity, which forms the interpeptidic cross-link N(epsilon)-(gamma-glutamyl)-lysine, was demonstrated in cell-free extracts of Saccharomyces cerevisiae by incorporation of [(14)C]lysine into an exogenous acceptor, N,N'-dimethylcasein. Higher levels of the activity were present in the cell wall, which also contained endogenous acceptors. The enzyme activity in the wall was inhibited by cystamine, a known inhibitor of transglutaminase, and by EDTA, indicating a cation-dependent activity. After the endogenous wall acceptors were labelled radioactively by transglutaminase, extraction with SDS solubilized about 50% of the total radioactivity, while Zymolyase and chitinase each…
Nitric oxide as neuromodulator of sympathetic transmission in rat vas deferens.
1998
Summary Electrical field stimulation (EFS) of muscle strips in vitro elicited a tetrodotoxin (TTX)-sensitive biphasic contractile response consisting of a phasic component followed by a tonic one. The amplitude of both components of the response was impaired by Nω-nitro-L-arginine and potentiated by sodium nitroprusside. Cystamine caused a reduction in amplitude of both phasic and tonic componets of the response to EFS. Neither Nω-nitro-L-arginine, sodium nitroprusside, nor cystamine induced changes in the resting muscle tone, or in the contractile response to exogenous agonists ATP and noradrenaline (NA). The nitric oxide scavenger, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, i…
Synthesis of Amphiphilic Block Copolypept(o)ides by Bifunctional Initiators: Making PeptoMicelles Redox Sensitive.
2015
In this work, the synthesis of polypeptoid-block-polypeptide copolymers (block copolypept(o)ides) based on bifunctional initiators is described, which introduces a distinct chemical entity at the connection between both blocks. With a view towards redox-sensitive block copolypept(o)ides, a cystamine-based initiator was used to synthesize polysarcosine macroinitiators with degrees of polymerization (Xn) between 100 and 200 displaying monomodal molecular weight distributions and dispersities (Đ) around 1.1 as determined by size exclusion chromatography. Block copolypept(o)ides with a poly(γ-t-butyloxycarbonyl-L-glutamate) (PGlu(O(t) Bu)) block (Xn = 25 or 50) were synthesized by controlled N-…
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…
Combining inulin multifunctional polycation and magnetic nanoparticles: Redox-responsive siRNA-loaded systems for magnetofection
2019
Superparamagnetic Iron Oxide Nanoparticles (SPIONs) are recognized as one of the most promising agents for theranostic applications. Among methods designed for siRNA delivery, magnetofection, that is, nucleic acid cell uptake under the influence of a magnetic field acting on magnetic nucleic acid vectors, is emerging as a unique approach to combining advantages such as strong improvement of the kinetics of the delivery process and the possibility of localizing nucleic acid delivery to an area where the magnetic field is applied. This paper reports on the preparation of siRNA loaded magnetoplexes&mdash
Control of the ribulose 1,5-bisphosphate carboxylase/oxygenase activity by the chloroplastic glutathione pool.
2014
The CO2-fixing activity of ribulose 1,5-bisphosphate carboxylase/oxygenase depends on the redox state of its cysteines. Disulfides like cystamine or 5,5'-dithio-bis(2-nitrobenzoic acid), but not oxidized glutathione, switch the enzyme to the inactive oxidized form. Conversely, thiols like cysteamine, cysteine, dithiotreitol or 2-mercaptoethanol, but not reduced glutathione, recover enzymatic activity after a previous oxidation. Direct regulation of the carboxylase activity by the chloroplastic glutathione pool is hindered by kinetic barriers impeding access to the critical residues. However, reduced glutathione can drive the recovery of activity by means of minute amounts of smaller interme…