Search results for "SULFATE"

A Comparative Study of Poly(Azure A) Film-Modified Disposable Electrodes for Electrocatalytic Oxidation of H₂O₂: Effect of Doping Anion.

2018

In the present paper, poly(azure A) (PAA) films were electrosynthetized in the presence of different doping anions on disposable screen-printed carbon electrodes (SPCEs). The anions used included inorganic monoatomic (chloride and fluoride), inorganic polyatomic (nitrate and sulfate) and organic polyatomic (dodecyl sulfate, DS) species. The coated electrodes thus obtained were characterized by electrochemical techniques and SEM. They showed improved electrocatalytic activities towards hydrogen peroxide oxidation compared to that of a bare SPCE. In particular, the insertion of DS anions inside PAA films provided a special sensitivity to the electrocatalysis of H2O2, which endowed these elect…

Absorption-partition relationships for true homologous series of xenobiotics as a possible approach to study mechanisms of surfactants in absorption.…

1992

Abstract This paper — the latest in this series of reports — deals with the effects of the anionic surfactant sodium lauryl sulfate on the colonic absorption of acidic xenobiotics (phenylalkylcarboxylic acids), as compared with those exerted by the nonionic polysorbate 80. The effects of these surfactants are qualitatively identical but quantitatively different. Thus, the increase in polarity of the colonic absorbant membrane is greater with lauryl sulfate, whereas micellar solubilization is much higher with polysorbate. As for the rest (i.e. the elimination of the stagnant aqueous diffusion layer as a limiting step for absorption), the two surfactants behave in a similar way. The biopharma…

Inhibition of glycosaminoglycan modification of perlecan domain I by site-directed mutagenesis changes protease sensitivity and laminin-1 binding act…

1998

AbstractGlycosaminoglycan attachment to perlecan domain I (173 residues) was completely prevented by site-directed mutagenesis of Ser-65, Ser-71 and Ser-76 as shown by recombinant production in mammalian cells. This did not interfere with the proper folding of the domain's SEA module but enhanced its sensitivity to neutral proteases. Lack of substitution also abolished binding to the two major heparin binding sites of laminin-1.

Analysis of serine proteases from marine sponges by 2-D zymography.

2007

Proteolytic activities isolated from the marine demosponges Geodia cydonium and Suberites domuncula were analyzed by 2-D zymography, a technique that combines IEF and zymography. After purification, a 200 kDa proteolytically active protein band was obtained from G. cydonium when analyzed in gelatin copolymerized 1-D zymograms. The enzymatic activity was quantified using alpha-N-benzoyl-D-arginine p-nitroanilide (BAPNA) as a substrate and corresponded to a serine protease. The protease activity was resistant to urea and SDS. DTT and 2-mercaptoethanol (2-ME) did not significantly change the protease activity, but induced a shift in molecular mass of the proteolytic band to lower M(r) values a…

Kinetic analysis and molecular modeling of the inhibition mechanism of roneparstat (SST0001) on human heparanase

2016

Heparanase is a β-d-glucuronidase which cleaves heparan sulfate chains in the extracellular matrix and on cellular membranes. A dysregulated heparanase activity is intimately associated with cell invasion, tumor metastasis and angiogenesis, making heparanase an attractive target for the development of anticancer therapies. SST0001 (roneparstat; Sigma-Tau Research Switzerland S.A.) is a non-anticoagulant 100% N-acetylated and glycol-split heparin acting as a potent heparanase inhibitor, currently in phase I in advanced multiple myeloma. Herein, the kinetics of heparanase inhibition by roneparstat is reported. The analysis of dose-inhibition curves confirmed the high potency of roneparstat (I…

A complex unfolding pathway of α-helical membrane proteins in SDS-containing micelles

2021

Heparan sulfate proteoglycans interact exclusively with conformationally intact HPV L1 assemblies: basis for a virus-like particle ELISA.

2004

In this article, we demonstrate that interaction of human papillomavirus-like particles (HPV-VLPs) with the putative glucosaminoglycan binding receptor is strictly dependent on conformational integrity. Such conformations are present on VLPs and capsomeres but not on monomers of the major capsid protein, L1, confirming reports that capsomeres can induce virus-neutralizing antibodies. Furthermore, we show the suitability of this specific interaction for development of VLP-based enzyme-linked immunosorbent assays (ELISAs), using heparin for indirect coupling of VLPs to microtiter plates, which may add an intrinsic quality control. This avoids presentation of linear, often highly cross-reactiv…

Polar/Ionizable Residues in Transmembrane Segments: Effects on Helix-Helix Packing

2012

The vast majority of membrane proteins are anchored to biological membranes through hydrophobic alpha-helices. Sequence analysis of high-resolution membrane protein structures show that ionizable amino acid residues are present in transmembrane (TM) helices, often with a functional and/or structural role. Here, using as scaffold the hydrophobic TM domain of the model membrane protein glycophorin A (GpA), we address the consequences of replacing specific residues by ionizable amino acids on TM helix insertion and packing, both in detergent micelles and in biological membranes. Our findings demonstrate that ionizable residues are stably inserted in hydrophobic environments, and tolerated in t…

The cytosolic Arabidopsis thaliana cysteine desulfurase ABA3 delivers sulfur to the sulfurtransferase STR18

2020

ABSTRACTThe biosynthesis of many sulfur-containing molecules depends on cysteine as a sulfur source. Cysteine desulfurase (CD) and rhodanese (Rhd) domain-containing protein families participate in the trafficking of sulfur for various metabolic pathways in bacteria and human, but their connection is not yet described in plants. The existence of natural chimeric proteins, however, containing both CD and Rhd domains in specific bacterial genera suggests a general interaction between both proteins. We report here the biochemical relationships between two cytosolic proteins from Arabidopsis thaliana, a Rhd domain containing protein, the sulfurtransferase 18 (STR18), and a CD isoform referred to…

Physicochemical compatibility and stability of nebulizable drug admixtures containing Dornase alfa and tobramycin.

2012

The objective of this in-vitro study was to determine whether admixtures of the inhalation solutions Pulmozyme(®) (Dornase alfa) and either Bramitob(®) or Tobi(®) (both containing Tobramycin) are physicochemically compatible and to analyze the aerodynamic parameters of these admixtures. After mixing, test solutions were stored at room temperature and under ambient light conditions over a period of 24 h. Tobramycin concentrations were determined by using a fluorescence immunoassay. Stability of dornase alfa was determined by size-exclusion high performance liquid chromatography, ultraviolet spectroscopy, sodium dodecyl sulfate polyacrylamide gel electrophoresis and tentacle strong cation-exc…