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PubMed2006

Geminate proton recombination at the surface of SDS and CTAC micelles probed with a micelle-anchored anthocyanin.

The functionalized flavylium salt 6-hexyl-7-hydroxy-4-methyflavylium chloride (HHMF) was employed to probe some of the fundamental features of proton transfer reactions at the surface of anionic sodium dodecyl sulfate (SDS) and cationic hexadecyltrimethylammonium chloride (CTAC) micelles. In contrast to most ordinary flavylium salts, HHMF is insoluble in water, but readily incorporates into SDS and CTAC micelles. In the ground state, the rate constant for deprotonation of the acid form (AH+) of HHMF decreases 100-fold upon going from CTAC (kd = 3.0 x 10(6) s(-1)) to SDS (kd = 1.4 x 10(4) s(-1)), consistent with the presence of an activation barrier for proton transfer in the ground state and reflecting, respectively, stabilization or destabilization of the AH+ cation by the micelle. Reprotonation of A is diffusion-controlled in both micelles (kp(SDS) = (2.1 x 10(11))[H+]aq s(-1) and kp(CTAC) = (3.7 x 10(8))[H+]aq s(-1)), the difference reflecting the rate of proton entry into the micelles. In the excited singlet state, the rate constants for deprotonation of the AH+* form of HHMF are similar in the two micelles (2.4 x 10(10) s(-1)), consistent with activationless proton transfer. Reprotonation of the excited A is dominated by fast geminate recombination of the photogenerated (A*-H+) pair at the micelle surface (k(rec)(SDS) = 6.1 x 10(9) s(-1) and k(rec)(CTAC) = 3.4 x 10(10) s(-1)) and the net efficiencies of geminate recombination are quite similar in SDS (0.89) and CTAC (0.86).

Anthocyanins↗
PubMed2002

Determining a diagnostic cut-off on the Severity of Dependence Scale (SDS) for cocaine dependence.

AIM: The study aimed to assess the efficacy of the Severity of Dependence Scale (SDS) as a diagnostic measure of cocaine dependence and determine the cut-off score that best discriminates between the presence and absence of a DSM-IV diagnosis of cocaine dependence. DESIGN: Cross-sectional survey. SETTING: Sydney, Australia. PARTICIPANTS: One hundred and forty-two cocaine users. MEASUREMENTS: The diagnostic performance of the SDS was measured via ROC analysis against DSM-IV diagnoses of cocaine dependence, as measured by the Composite International Diagnostic Interview (CIDI). FINDINGS: ROC analysis revealed the SDS to be a test of high diagnostic utility for the measurement of cocaine dependence. The cut-off point on the SDS at which there is optimal discrimination between the presence and absence of a DSM-IV diagnosis of cocaine dependence was found to be 3 (i.e. a score of 3 or more). CONCLUSIONS: The study statistically validated the utility of the SDS as a diagnostic measure of cocaine dependence and has determined an appropriate cut-off point. The SDS is recommended as a brief screening instrument for cocaine dependence that can be used in addition to more comprehensive measures, such as the CIDI.

Adolescent↗
PubMed1997

Modification of T-cell antigenic properties of tetanus toxoid by SDS-PAGE separation. Implications for T-cell blotting.

Using Tetanus Toxoid (TT) as a model antigen the T-cell Blotting method was evaluated. Peripheral blood mononuclear cell (PBMC) cultures were stimulated by blotted nitrocellulose-bound TT or soluble TT. SDS-Poly-Acrylamide-Gel-Electrophoresis separated TT only induced proliferation in 20% of the PBMC cultures whereas proliferation was induced in 79% of the same cultures offered similar treated TT (except for the PAGE separation). When T-cell blotting was performed with TT separated in a SDS-agarose matrix, proliferation was induced in 80% of donors responding to soluble TT. The results show that SDS-PAGE alters the ability of TT to induce T-cell proliferation, possibly due to unpolymerized acrylamide binding to proteins during SDS-PAGE. The use of SDS-PAGE T-cell blotting in the screening for T-cell antigens must therefore be reconsidered. We suggest the use of SDS-Agarose Gel Electrophoresis as an alternative when doing T-cell blots.

Acrylamide↗
PubMed2002

SDS-PAGE is underutilized as a tool for investigating renal patients.

SDS-PAGE is an excellent single test for investigating proteinuria. It can provide much useful information on the underlying renal problem. Yet the literature hardly report a SDS-PAGE result in the management of renal patients. To examine how closely SDS-PAGE results may reflect biopsy findings, we investigated 11 patients scheduled for renal biopsy. Urine samples were taken at the same time for SDS-PAGE analysis using the PhastSystem (Pharmacia, Sweden). Comparing biopsy findings and SDS-PAGE results, the data show consistency in the revelation of tubular dysfunction and/or glomerular damage in all 11 patients. We concluded that the SDS-PAGE test is underutilized and suggest that its role for the management of renal patients be fully explored particularly in its potential for reducing the need for renal biopsy in certain patient groups.

Adolescent↗
PubMed2000

Beta 57-Asp plays an essential role in the unique SDS stability of HLA-DQA1*0102/DQB1*0602 alpha beta protein dimer, the class II MHC allele associated with protection from insulin-dependent diabetes mellitus.

Studies of the stability of HLA-DQ have revealed a correlation between SDS stability of MHC class II alphabeta dimers and insulin-dependent diabetes mellitus (IDDM) susceptibility. The MHC class II alphabeta dimer encoded by HLA-DQA1*0102/DQB1*0602 (DQ0602), which is a dominant protective allele in IDDM, exhibits the greatest SDS stability among HLA-DQ molecules in EBV-transformed B-lymphoblastoid cells and PBLs. DQ0602 is also uniquely SDS stable in the HLA-DM-deficient cell line, BLS-1. We addressed the molecular mechanism of the stability of DQ0602 in BLS-1. A panel of mutants based on the polymorphic differences between HLA-DQA1*0102/DQB1*0602 and HLA-DQA1*0102/DQB1*0604 were generated and expressed in BLS-1. An Asp at beta57 was found to be critical for SDS stability, whereas Tyr at beta30, Gly at beta70, and Ala at beta86 played secondary roles. Furthermore, the level of class II-associated invariant chain peptide bound to HLA-DQ did not correlate with SDS stability, suggesting that class II-associated invariant chain peptide does not play a direct role in the unique SDS stability of DQ0602. These results support a role for DQB1 codon 57 in HLA-DQ alphabeta dimer stability and IDDM susceptibility.

Alleles↗
PubMed2005

[Study on sodium lauryl sulfate (SDS) induced fluorescence enhancement of rhodamine 6G in water solution excited by 532 nm laser].

It is reported that the Rhodamine 6G fluorescence in water solution changes with different concentration SDS excited by a 532 nm laser. A small amount of SDS in Rhodamine 6G water solution will reduce the intensity of fluorescence. More SDS enhances R6G fluorescence. The enhancement ratio can reach up to 3.1 when SDS concentration is 6 x 10(-2) mol L(-1) in 5 x 10(-5) mol L(-1) R6G water solution. Dye laser threshold decreases when SDS concentration is 2 x 10(-2) mol x L(-1) in 1 x 10(-4) mol x L(-1) R6G water solution. The physical mechanism of the phenomena is analyzed by the absorption spectra of different concentration R6G water solutions and the fluorescence spectra of R6G water solutions adulterated with different concentration SDS.

Fluorescence↗
PubMed1987

Comparison of subcellular activation of the human neutrophil NADPH-oxidase by arachidonic acid, sodium dodecyl sulfate (SDS), and phorbol myristate acetate (PMA).

The phorbol myristate acetate (PMA) stimulation of the human neutrophil NADPH-oxidase has been demonstrated through the activation of protein kinase C (PK-C), using light membrane fractions from nitrogen-cavitated cells. Both arachidonic acid (AA) and sodium dodecyl sulfate (SDS) can also generate an active oxidase in cellfree systems. That the source of O2- with AA and SDS activation is the same NADPH-oxidase as previously studied was confirmed by the similar pH optima and Km values for NADPH as those previously described for the O2- -generating activity harvested from pre-stimulated human neutrophils. In contrast to the stimulation by PMA, however, the stimulation of the NADPH-oxidase by AA and SDS does not appear to require protein kinase C activation: the action of AA and SDS is independent of the addition of PK-C cofactors to the system, and the inhibitor of PK-C activity, H-7, had no effect on the stimulation by AA or SDS. AA and SDS activation are comparable, but the level of NADPH-oxidase expression is sixfold greater with each of these agents than that obtained with a reconstituted PK-C system. The basis of this difference in oxidase expression is unclear, but these findings suggest strongly that although activated PK-C is capable of stimulating a dormant NADPH-oxidase in a cellfree system, this is not the sole pathway for oxidase activation.

Arachidonic Acid↗
PubMed1991

Separation of proteins by consecutive sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis and reversed phase high performance liquid chromatography.

A procedure for the preparative separation of proteins was developed by using consecutively sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (SDS-PAGE) and reversed phase high performance liquid chromatography (HPLC). The proteins were separated by SDS-PAGE and afterwards extracted from the gel. The extracted proteins were separated from SDS and other small molecular weight contaminants on a Fractogel TSK HW-40 (F) column in acidic aqueous acetonitrile. The proteins eluted from the Fractogel column were fractionated by HPLC. The identity and purity of the recovered proteins was confirmed by SDS-PAGE analysis.

Chromatography, Gel↗
PubMed1999

Precipitation of dilute chromatographic samples (ng/ml) containing interfering substances for SDS-PAGE.

SDS-PAGE of chromatographic fractions requires prior removal of salts, detergents, denaturants, or organic solvents which may perturb the electrophoretic separation. Likewise, to successfully visualize minute amounts of protein present in chromatographic fractions, they must often be concentrated before analysis by SDS-PAGE. In this study, we used a dye precipitation procedure for simultaneous removal of interfering substances and concentration of dilute samples (ng/ml) before analysis by SDS-PAGE. Nanogram amounts of protein (143 ng) were effectively precipitated with a pyrogallol red-molybdate reagent from commonly used chromatographic buffers containing various interfering solutes or solvents. Proteins were successfully precipitated from solution in the presence of organic solvents (acetonitrile, methanol, 2-propanol), chaotropic agents (6 M urea, 6 M guanidine-HCl), a protein stabilizer (40% sucrose), metal chelators (30 mM EDTA and 30 mM EGTA), or high salt (1.0 M NaCl). Detergents, at concentrations up to twice their critical micelle concentrations, from the nonionic class (Triton X-100, Tween 20) or from the zwitterionic class (3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate) did not inhibit protein precipitation. Some interference was observed when proteins were precipitated in the presence of ammonium sulfate (0. 5-2.0 M). Proteins did not precipitate in the presence of ionic detergents (SDS and cetyltrimethylammonium bromide). The sensitivity of the combined pyrogallol red-molybdate precipitation/SDS-PAGE procedure is approximately 7 ng. Two other methods of precipitating proteins (trichloroacetic acid and phenol-ether) both exhibited varying degrees of effectiveness, ranging from 714 to 7 ng/ml, in the precipitation of individual proteins. In summary, the pyrogallol red-molybdate protein precipitation procedure facilitates the SDS-PAGE analysis of dilute protein samples (ng/ml) from chromatographic fractions of various compositions. The method is useful for rapid pilot-scale protein fractionation and facilitates the ongoing propensity of researchers to work with minuscule amounts of protein.

Chemical Precipitation↗
PubMed2000

Interaction of Chlorpromazine and Trifluoperazine with Anionic Sodium Dodecyl Sulfate (SDS) Micelles: Electronic Absorption and Fluorescence Studies.

The characteristics of binding of two phenothiazine antipsychothic drugs, chlorpromazine (CPZ) and trifluoperazine (TFP), to anionic sodium dodecyl sulfate (SDS) monomers and/or micelles were investigated using electronic absorption and fluorescence spectroscopies. Binding constants K(b) and pK(a) values for the drugs in SDS micelles were estimated using the red shifts of the maximum absorption and changes in absorption upon alkalization or in the presence of surfactant. The pK(a) shift of CPZ due to its interaction with SDS micelles is about 0.7 unit to higher values, as compared to the reported value of pK(a) obtained in buffer around 9.3. For TFP the pK(a) shift is 0.4 unit to higher values compared to that in buffer, reported as 4.0. The electronic absorption spectroscopic data suggest a biphasic interaction as a function of detergent concentration which is quite dependent of the protonation states of the drugs. In the case of TFP a very strong binding takes place when the drug is fully protonated (pH 2.0) and a distinct binding takes place at stoichiometric (low) surfactant concentrations (interaction via surfactant monomers) and at higher concentrations (in the presence of micelles). Static fluorescence probe analysis using pyrene was used to study the nature of the phenothiazine-surfactant premicellar and self-aggregates. The I(3)/I(1) and I(475)/I(1) ratios associated to pyrene fluorescence vibronic bands and excimer intensities ratios, respectively, were monitored for several ratios [SDS]/[drug] and significant changes, dependent of the drug presence and its protonation state, have been observed revealing a hydrophobic microenvironment provided by TFP-SDS aggregates in comparison with CPZ both at pH 7.0 and 4.0. Static anisotropy was also used to monitor the changes of the self-aggregates and micellar packing in the presence of the phenothiazine drugs. In aqueous solutions the anisotropy of the fluorescent probe dipyridamole (DIP) is quite low, being around 0.005 at pH 7.0 and 0.025 at pH 4.0, and the addition of detergent leads to an increase in the values of anisotropy to 0.030 at pH 7.0 and 0.070 at pH 4.0. In the presence of the phenothiazine drugs, and in the premicellar detergent concentration range, the anisotropy of DIP increases to 0.134 and 0.111 (dependent on drug concentration) for CPZ and TFP, respectively, at pH 4.0. These results suggest that the presence of both phenotiazine drugs makes the premicellar aggregates more rigid by decreasing the probe mobility, and are consistent with a more polar localization of the CPZ in the micelles as compared with TFP. At pH 7.0 the anisotropy changes are smaller, suggesting a slight decrease in CMC induced by the phenothiazines. Copyright 2000 Academic Press.

Journal Article↗
PubMed2002

Selective foam separation of binary protein solution by SDS complexation method.

A fundamental study about the selective foam separation of protein mixture was carried out. A solution containing two proteins, ovalbumin (OA) and lysozyme (LZ), and an anionic surfactant, sodium dodecyl sulfate (SDS), was adjusted to pH 6.0, which referred to an intermediate state between the isoelectric points of the proteins. The solution was processed by continuous foam separation. The results showed that a proper addition of SDS greatly improved the selective recovery of LZ to OA. The experimental data were well explained by a simple model that most of cationic protein molecules (LZ) are associated with SDS and the adsorption of all the species including LZ-SDS complexes are subjected to Langmuir adsorption isotherm. The results also showed that one of the Langmuir parameters, which means a kind of lyophillic property of adsorbed material, of LZ-SDS complexes was extremely large as compared with that of primary protein.

Absorption↗
PubMed1988

Purification of membrane proteins in SDS and subsequent renaturation.

A prerequisite for the purification of any protein to homogeneity is that the protein is not non-specifically associated with other proteins especially during the final stage(s) of the fractionation procedure. This requirement is not so often fulfilled when nonionic detergents (for instance Triton X-100) are used for solubilization of membrane proteins. The reason is that these detergents are not efficient enough to prevent the protein of interest from forming aggregates with other proteins upon contact with chromatographic or electrophoretic supporting media, which, due to their polymeric nature, have a tendency to induce aggregation of other polymers, for instance, hydrophobic proteins. The aggregation can be avoided if sodium dodecyl sulfate (SDS) is employed as detergent. We therefore suggest that membrane proteins should be purified by conventional methods in the presence of SDS and that the purified proteins, which are in a denatured state, are allowed to renature. There is good change to renature internal membrane proteins since they should not be so susceptible to denaturation by detergents as are water-soluble proteins because the natural milieu of the former proteins is lipids which in fact are detergents. In this paper we present a renaturation method based on the removal of SDS by addition of a large excess of G 3707, a nonionic detergent. By this technique we have renatured a 5'-nucleotidase from Acholeplasma laidlawii and a neuraminidase from influenza virus. The enzyme activities were higher (up to 6-fold) after the removal of SDS than prior to the addition of SDS.

5'-Nucleotidase↗
PubMed1980

Solubilization of oil-soluble dyes by sodium dodecyl sulfate-protein polypeptide complexes with reference to SDS-polyacrylamide gel electrophoresis.

Sodium dodecyl sulfate binds to the linear polypeptide derived from a protein to form micelle-like clusters (Takagi, T., Tsujii, K. and Shirahama, K. (1975) J. Biochem. 78, 939--947) which are expected to solubilize lipophilic materials. Such clusters were found to afford the complexes strong solubilizing power against oil-soluble dyes, comparable or slightly superior to SDS micelles, by conventional solubilizing technique (equilibration with solid dye) and by gel chromatography technique first applied to measure solubilization by such complexes. Solubilization behavior of the bound SDS was insensitive to the kind of protein polypeptide, in contrast to the variety found in the pioneering similar study on the complexes between SDS and initially native proteins (Steinhardt, J., Stocker, N., Carroll, D. and Birdi, K.S. (1977) Biochemistry 16, 718--725). The knowledge of the solubilizing power of SDS-protein polypeptide complexes seems to be valuable in design of experiments and interpretation of results obtained in application of SDS-polyacrylamide gel electrophoresis to samples containing lipophilic materials.

Colloids↗
PubMedDate not supplied

Removal of SDS from proteins for immunochemical analyses: a simple method utilizing ultracentrifugation in sucrose density gradients containing non-ionic detergent.

A simple method for removal of SDS from proteins is described. SDS-treated proteins are centrifuged through sucrose density gradients containing Triton X-100. Proteins possessing sedimentation coefficients of > 4 S separate from the bulk of SDS, which remains at the top of the sucrose gradients. Quantitative immunoelectrophoretic analyses of SDS-treated human serum proteins and human erythrocyte membrane proteins indicate that the majority of the proteins tested is subsequently precipitable with specific antisera. Initial membrane solubilization with SDS can thus be followed up by a fractionation step that will yield many proteins in a state immediately suitable for bioimmunochemical analyses.

Blood Proteins↗
PubMed1982

Interaction between the alpha 1 chain of rat tail collagen and sodium dodecyl sulfate with reference to its behaviour in SDS-polyacrylamide gel electrophoresis.

The interaction between the alpha 1 chain of rat tail collagen and sodium (SDS) was studied to provide knowledge necessary to understand the behavior of the complex between them in a molecular sieving technique such as SDS-polyacrylamide gel electrophoresis. Measured properties include binding isotherm, CD spectrum, viscosity and behavior in free boundary electrophoresis, gel electrophoresis and high-pressure silica gel chromatography. The complex differed in most respects from the complexes between SDS and polypeptides derived from water-soluble globular proteins, reflecting its peculiar amino acid composition. THe hydrodynamically effective volume of the SDS-alpha 1 chain complex was the most significantly different among the properties studied. The complex of the alpha 1 chain consisted of 1052 amino acid residues and was found to have the same effective volume as that of a standard polypeptide consisting of about 800 residues. The abnormal behaviour of the SDS-alpha 1 chain complex was interpreted on the basis of these results.

Animals↗
PubMed2005

SDS-aided immobilization and controlled release of camptothecin from agarose hydrogel.

Camptothecin (CPT), known to be an effective anticancer drug, has a limited therapeutic utility because of its poor water solubility. In this work, an approach has been made to overcome the limitation. CPT was first incorporated into the micelles formed from an ionic surfactant, sodium dodecyl sulfate (SDS) and the micellar drug aqueous solution was then used in preparation of the agarose hydrogel. It has been found that the presence of SDS greatly increased the solubility of CPT in water. For example, in 1 ml of 1.0 wt.% SDS water solution, 0.11 mg CPT could be solubilized (0.318 mM), which was 83 times the solubility in pure water. It was the hydrophobic cores of the SDS micelles that were able to accept the lipophilic drug to form stable drug-immobilized micelles. The formulation of a hydrogel using the drug-immobilized micelles has allowed us to obtain a unique and novel drug release system where the drug molecules are encapsulated by the micelles and the drug-containing micelles are dispersed in the gel network. The release of CPT from the so deliberately fabricated agarose hydrogel system has been studied as a function of surfactant concentration at 37 degrees C. The diffusion coefficients of CPT obtained by fitting to Fick's law ranged from 2.12 to 7.36 x 10(-7)cm(2)s(-1). The results showed that SDS prolonged the drug release by reducing the diffusion coefficient of CPT in the gel.

Antineoplastic Agents, Phytogenic↗
PubMed1992

Protein structures in SDS micelle-protein complexes.

Sodium dodecyl sulfate (SDS) is used more often than any other detergent as an excellent denaturing or "unfolding" detergent. However, formation of ordered structure (alpha-helix or beta-sheet) in certain peptides is known to be induced by interaction with SDS micelles. The SDS-induced structures formed by these peptides are amphiphilic, having both a hydrophobic and a hydrophilic face. Previous work in this area has revealed that SDS induces helical folding in a wide variety of non-helical proteins. Here, we describe the interaction of several structurally unrelated proteins with SDS micelles and the correlation of these structures to helical amphiphilic regions present in the primary sequence. It is likely that the ability of native nonordered protein structures to form induced amphiphilic ordered structures is rather common.

Animals↗
PubMed2000

Transfer of SDS-proteins from gel electrophoretic zones into mass spectrometry, using electroelution of the band into buffer without sectioning of the gel.

Five SDS-proteins, ranging in molecular weight from 14 to 66 kDa, were detected without covalent fluorescent labeling by the automated gel electrophoresis apparatus with intermittent fluorescence scanning (HPGE apparatus, LabIntelligence) during electrophoresis in barbiturate buffer in the presence of Cascade Blue. The SDS-proteins were electroeluted from the gel into 220 microl of buffer by a modification of the procedure of Gombocz and Cortez. The electroeluate was freed of SDS, ultrafiltered and subjected to MALDI-TOF mass spectrometry. The masses of the five native proteins were found to be maintained after electrophoresis and electroelution in the presence of the potential contaminants SDS, barbituric acid and Cascade Blue. The procedure of protein transfer from SDS-PAGE into mass spectrometry, without excision of bands, gel maceration and protein recovery by diffusion, therefore is shown to be suitable for the identification by mass of intact proteins derived from gel electrophoretic bands.

Biochemistry↗