Sigma-Aldrich

Ammonium sulfate anhydrous, Redi-Dri™, ReagentPlus®, ≥99.0%; CAS Number: 7783-20-2; Synonyms: Mascagnite; Linear Formula: (NH4)2SO4; find Sigma-Aldrich-901874 MSDS, related peer-reviewed papers, technical documents, similar products & more at Sigma-Aldrich

Ammonium sulfate anhydrous, Redi-Dri, ReagentPlus, = 99.0 7783-20-2

anhydrous, Redi-Dri&#8482;, ReagentPlus&#174;, &#8805;99.0%

Ammonium sulfate anhydrous, Redi-Dri&#8482;, ReagentPlus&#174;, &#8805;99.0%

Ammonium sulfate

The 1-by-3 tandem differential mobility analyzer for measurement of the irreversibility of the hygroscopic growth factor.

Substitutes for Ammonium Sulfate as Additives with Glyphosate and Glufosinate.

Ammonium Compounds.

Industrial catalytic aspects of the synthesis of monomers for nylon production.

Influence of yeast strain on Shiraz wine quality indicators.

MshB, a zinc-based deacetylase, catalyses a step in the mycothiol biosynthetic pathway that involves the deacetylation of 1-O-(2-acetamido-2-deoxy-α-D-glucopyranosyl)-D-myo-inositol (GlcNAc-Ins), via cleavage of an amide bond, to 1-O-(2-amino-2-deoxy-α-D-glucopyranosyl)-D-myo-inositol (GlcN-Ins) and acetate. In this study, MshB was expressed, purified and crystallized. A new crystal form was encountered in 0.1 M sodium acetate, 0.2 M ammonium sulfate, 25% PEG 4000 pH 4.6. The crystals diffracted to 1.95 Å resolution and the resulting electron-density map revealed glycerol and the reaction product, acetate, in the active site. These ligands enabled the natural substrate GlcNAc-Ins to be modelled in the active site with some certainty. One acetate O atom is hydrogen bonded to Tyr142 and is located 2.5 Å from the catalytic zinc. The other acetate O atom is located 2.7 Å from a carboxylate O atom of Asp15. This configuration strongly suggests that Asp15 acts both as a general base catalyst in the nucleophilic attack of water on the amide carbonyl C atom and in its protonated form acts as a general acid to protonate the amide N atom. The configuration of Tyr142 differs from that observed previously in crystal structures of MshB (PDB entries 1q74 and 1q7t) and its location provides direct structural support for recently published biochemical and mutational studies suggesting that this residue is involved in a conformational change on substrate binding and contributes to the oxyanion hole that stabilizes the tetrahedral intermediate.

A new crystal form of MshB from Mycobacterium tuberculosis with glycerol and acetate in the active site suggests the catalytic mechanism.

A large number of organic species emitted into the atmosphere contain cycloalkyl groups. While cyclic species are believed to be important secondary organic aerosol (SOA) precursors, the specific role of cyclic moieties (particularly for species with multiple or fused rings) remains uncertain. Here we examine the yields and composition of SOA formed from the reaction of OH with a series of C10 (cyclo)alkanes, with 0-3 rings, in order to better understand the role of multiple cyclic moieties on aerosol formation pathways. A chamber oxidation technique using high, sustained OH radical concentrations was used to simulate long reaction times in the atmosphere. This aging technique leads to higher yields than in previously reported chamber experiments. Yields were highest for cyclic and polycyclic precursors, though yield exhibited little dependence on number of rings. However, the oxygen-to-carbon ratio of the SOA was highest for the polycyclic precursors. These trends are consistent with aerosol formation requiring two generations of oxidation and 3-4 oxygen-containing functional groups in order to condense. Cyclic, unbranched structures are protected from fragmentation during the first oxidation step, with C-C bond scission instead leading to ring opening, efficient functionalization, and high SOA yields. Fragmentation may occur during subsequent oxidation steps, limiting yields by forming volatile products. Polycyclic structures can undergo multiple ring opening reactions, but do not have markedly higher yields, likely due to enhanced fragmentation in the second oxidation step. By contrast, C-C bond scission for the linear and branched structures leads to fragmentation prior to condensation, resulting in low SOA yields. The results highlight the key roles of multigenerational chemistry and susceptibility to fragmentation in the formation and evolution of SOA.

Secondary organic aerosol formation from acyclic, monocyclic, and polycyclic alkanes.

Cellulose fibers were engineered by in situ oxidative polymerization of aniline using ammonium persulfate as oxidant/initiator. The polyaniline/cellulose fiber composite was used for the treatment of Cr(VI)-contaminated water, and its effect was evaluated. Under the conditions studied, the composite exhibited very high water detoxification efficiency, as a result of reduction of Cr(VI) to Cr(III) in combination with adsorption of the Cr(III) onto the cellulosic substrate. Cellulose fibers used in the study served two purposes simultaneously, i.e., carrier of polyaniline and the adsorbent for Cr(III). The complexation of polyaniline with cellulose fibers provided synergistic effects on Cr(VI)-detoxification.

Polyaniline/cellulose fiber composite prepared using persulfate as oxidant for Cr(VI)-detoxification.

Chaperonins are ubiquitous molecular chaperones with the subunit molecular mass of 60kDa. They exist as double-ring oligomers with central cavities. An ATP-dependent conformational change of the cavity induces the folding of an unfolded protein that is captured in the cavity. In the group I chaperonins, which are present in eubacteria and eukaryotic organelles, inter-ring communication takes important role for the reaction cycle. However, there has been limited study on the inter-ring communication in the group II chaperonins that exist in archaea and the eukaryotic cytosol. In this study, we have constructed the asymmetric ring complex of a group II chaperonin using circular permutated covalent mutants. Although one ring of the asymmetric ring complex lacks ATPase or ATP binding activity, the other wild-type ring undergoes an ATP-dependent conformational change and maintains protein-folding activity. The results clearly demonstrate that inter-ring communication is dispensable in the reaction cycle of group II chaperonins.

Inter-ring communication is dispensable in the reaction cycle of group II chaperonins.

We studied the role of peroxisomal catalase in chronological aging of the yeastHansenula polymorpha in relation to various growth substrates. Catalase-deficient (cat) cells showed a similar chronological life span (CLS) relative to the wild-type control upon growth on carbon and nitrogen sources that are not oxidized by peroxisomal enzymes. However, when media contained methylamine, which is oxidized by peroxisomal amine oxidase, the CLS of cat cells was significantly reduced. Conversely, the CLS of cat cells was enhanced relative to the wild-type control, when cells were grown on methanol, which is oxidized by peroxisomal alcohol oxidase. At these conditions strongly enhanced ROS levels were observed during the exponential growth phase of cat cells. This was paralleled by activation of the transcription factor Yap1, as well as an increase in the levels of the antioxidant enzymes cytochrome c peroxidase and superoxide dismutase. Upon deletion of the genes encoding Yap1 or cytochrome c peroxidase, the CLS extension of cat cells on methanol was abolished. These findings reveal for the first time an important role of enhanced cytochrome c peroxidase levels in yeast CLS extension.

Peroxisomal catalase deficiency modulates yeast lifespan depending on growth conditions.

The yeast-like fungus Aureobasidium pullulans PL5 is a microbial antagonist against postharvest pathogens of fruits. The strain is able to produce hydrolases, including glucanases, chitinases and proteases. The alkaline serine protease gene ALP5 from A. pullulans was cloned, inserted into the vector pPIC9 to construct pPIC9/ALP5, and then expressed in Pichia pastoris strain KM71. ALP5 had a molecular mass of 42.9kDa after 5days growth with 1% methanol induction at 28°C. The recombinant protease expressed in P. pastoris showed its highest activity under alkaline conditions (at pH10) and a temperature of 50°C. The antifungal activity of the recombinant protease was investigated against Penicillium expansum, Botrytis cinerea, Monilinia fructicola and Alternaria alternata in vitro and on apple. The recombinant protease reduced significantly the spore germination and the germ tube length of the tested pathogens in PDB medium. The highest level of protease efficacy was observed against M. fructicola and B. cinerea, whereas a lower efficacy was observed against P. expansum and A. alternata indicating a possible effect of the pathogen cell wall composition on the proteolytic activity of the recombinant protease. The presence of protease was able to cause the swelling of the hyphae of B. cinerea, under an optical microscope. The recombinant protease expressed in P. pastoris was more active against the pathogens in vitro than the same enzyme expressed in E. coli in previous studies. The efficacy of ALP5 was also evaluated against the pathogens in vivo on cv Golden Delicious apples. The protease was more efficient in controlling M. fructicola, B. cinerea and P. expansum than A. alternata. However, the extent of the activity was dependent on the enzyme concentration and the length of fruit storage. This study demonstrated the capacity of the alkaline serine protease to keep its enzymatic activity for some days in the unfavorable environment of the fruit wounds. The alkaline serine protease could be developed as a postharvest treatment with antimicrobial activity for fruit undergoing a short storage period.

Biocontrol activity of an alkaline serine protease from Aureobasidium pullulans expressed in Pichia pastoris against four postharvest pathogens on apple.

Intracellular redox state is a critical factor for fundamental cellular functions, including regulation of the activities of various metabolic enzymes as well as ROS production and elimination. Genetically-encoded fluorescent redox sensors, such as roGFP (Hanson, G. T., et al. (2004)) and Redoxfluor (Yano, T., et al. (2010)), have been developed to investigate the redox state of living cells. However, these sensors are not useful in cells that contain, for example, other colored pigments. We therefore intended to obtain simpler redox sensor proteins, and have developed oxidation-sensitive fluorescent proteins called Oba-Q (oxidation balance sensed quenching) proteins. Our sensor proteins derived from CFP and Sirius can be used to monitor the intracellular redox state as their fluorescence is drastically quenched upon oxidation. These blue-shifted spectra of the Oba-Q proteins enable us to monitor various redox states in conjunction with other sensor proteins.

Redox sensor proteins for highly sensitive direct imaging of intracellular redox state.

The last two steps of l-tryptophan (Trp) biosynthesis are catalyzed by Trp synthase, a heterotetramer composed of TrpA and TrpB. TrpB catalyzes the condensation of indole, synthesized by TrpA, and serine to Trp. In the hyperthermophilic archaeon Thermococcus kodakarensis, trpA and trpB (trpB1) are located adjacently in the trpCDEGFB1A operon. Interestingly, several organisms possess a second trpB gene (trpB2) encoding TrpB2, located outside of the trp operon in T. kodakarensis. Until now, the physiological function of trpB2 has not been examined genetically. In the present study, we report the biochemical and physiological analyses of TrpB2 from T. kodakarensis. Kinetic analysis indicated that TrpB2 catalyzed the TrpB reaction but did not interact with TrpA as in the case of TrpB1. When growth phenotypes were examined for gene disruption strains, the double-deletion mutant (ΔtrpB1ΔtrpB2) displayed Trp auxotrophy, whereas individual single mutants (ΔtrpB1 and ΔtrpB2 strains) did not. It has been proposed previously that, in Thermotoga maritima, TrpB2 provides an alternate route to generate Trp from serine and free indole (indole salvage). To accurately examine the capacity of TrpB1 and TrpB2 in Trp synthesis via indole salvage, we constructed ΔtrpEB1 and ΔtrpEB2 strains using strain KUW1 (ΔpyrFΔtrpE) as a host, eliminating the route for endogenous indole synthesis. Indole complemented the Trp auxotrophies of ΔtrpEB1 (ΔpyrFΔtrpEΔtrpB1) and ΔtrpEB2 (ΔpyrFΔtrpEΔtrpB2) to similar levels. The results indicate that TrpB1 and TrpB2 both contribute to Trp biosynthesis in T. kodakarensis and can utilize free indole, and that indole salvage does not necessarily rely on TrpB2 to a greater extent.

The tryptophan synthase β-subunit paralogs TrpB1 and TrpB2 in Thermococcus kodakarensis are both involved in tryptophan biosynthesis and indole salvage.

Modularity in controlling gene expression artificially is becoming an essential aspect of synthetic biology. Artificial transcriptional control of gene expression is one of the most well-developed methods for the design of novel synthetic regulatory networks. Such networks are intended to help understand natural cellular phenomena and to enable new biotechnological applications. Promoter sequence manipulation with cis-regulatory elements is a key approach to control gene expression transcriptionally. Here, we have designed a promoter that can be both activated and repressed, as a contribution to the library of synthetic biological 'parts'. Starting with the minimal cytochrome C (minCYC) promoter in yeast, we incorporated five steroid hormone responsive elements (SHREs) and one lac operator site, respectively, upstream and downstream of the TATA box. This allows activation through the testosterone-responsive androgen receptor, and repression through the LacI repressor. Exposure to varying concentrations of testosterone (to vary activation) and IPTG (to vary repression) demonstrated the ability to tune the promoter's output curve over a wide range. By integrating activating and repressing signals, the promoter permits a useful form of signal integration, and we are optimistic that it will serve as a component in future regulatory networks, including feedback controllers.

Design and characterization of a dual-mode promoter with activation and repression capability for tuning gene expression in yeast.

S-Adenosyl-L-methionine (SAM) is a major biological methyl group donor, and is used as a nutritional supplement and prescription drug. Yeast is used for the industrial production of SAM owing to its high intracellular SAM concentrations. To determine the regulation mechanisms responsible for such high SAM production, (13)C-metabolic flux analysis ((13)C-MFA) was conducted to compare the flux distributions in the central metabolism between Kyokai no. 6 (high SAM-producing) and S288C (control) strains. (13)C-MFA showed that the levels of tricarboxylic acid (TCA) cycle flux in SAM-overproducing strain were considerably increased compared to those in the S228C strain. Analysis of ATP balance also showed that a larger amount of excess ATP was produced in the Kyokai 6 strain because of increased oxidative phosphorylation. These results suggest that high SAM production in Kyokai 6 strains could be attributed to enhanced ATP regeneration with high TCA cycle fluxes and respiration activity. Thus, maintaining high respiration efficiency during cultivation is important for improving SAM production.

(13)C-metabolic flux analysis in S-adenosyl-L-methionine production by Saccharomyces cerevisiae.

The precise control of gene expression is essential in basic biological research as well as in biotechnological applications. Most regulated systems available in yeast enable only the overexpression of the target gene, excluding the possibility of intermediate or weak expression. Moreover, these systems are frequently toxic or depend on growth conditions. We constructed a heterologous transcription factor that overcomes these limitations. Our system is a fusion of the bacterial LexA DNA-binding protein, the human estrogen receptor (ER) and an activation domain (AD). The activity of this chimera, called LexA-ER-AD, is tightly regulated by the hormone β-estradiol. The selection of the AD proved to be crucial to avoid toxic effects and to define the range of activity that can be precisely tuned with β-estradiol. As our system is based on a heterologous DNA-binding domain, induction in different metabolic contexts is possible. Additionally, by controlling the number of LexA-binding sites in the target promoter, one can scale the expression levels up or down. Overall, our LexA-ER-AD system is a valuable tool to precisely control gene expression in different experimental contexts without toxic side effects.

Inducible, tightly regulated and growth condition-independent transcription factor in Saccharomyces cerevisiae.

Friedreich's ataxia is a severe neurodegenerative disease caused by the decreased expression of frataxin, a mitochondrial protein that stimulates iron-sulfur (Fe-S) cluster biogenesis. In mammals, the primary steps of Fe-S cluster assembly are performed by the NFS1-ISD11-ISCU complex via the formation of a persulfide intermediate on NFS1. Here we show that frataxin modulates the reactivity of NFS1 persulfide with thiols. We use maleimide-peptide compounds along with mass spectrometry to probe cysteine-persulfide in NFS1 and ISCU. Our data reveal that in the presence of ISCU, frataxin enhances the rate of two similar reactions on NFS1 persulfide: sulfur transfer to ISCU leading to the accumulation of a persulfide on the cysteine C104 of ISCU, and sulfur transfer to small thiols such as DTT, L-cysteine and GSH leading to persulfuration of these thiols and ultimately sulfide release. These data raise important questions on the physiological mechanism of Fe-S cluster assembly and point to a unique function of frataxin as an enhancer of sulfur transfer within the NFS1-ISD11-ISCU complex.

Mammalian frataxin directly enhances sulfur transfer of NFS1 persulfide to both ISCU and free thiols.

Chemoresistance is a primary cause of treatment failure in cancer and a common property of tumor-initiating cancer stem cells. Overcoming mechanisms of chemoresistance, particularly in cancer stem cells, can markedly enhance cancer therapy and prevent recurrence and metastasis. This study demonstrates that the delivery of Epirubicin by nanodiamonds is a highly effective nanomedicine-based approach to overcoming chemoresistance in hepatic cancer stem cells. The potent physical adsorption of Epirubicin to nanodiamonds creates a rapidly synthesized and stable nanodiamond-drug complex that promotes endocytic uptake and enhanced tumor cell retention. These attributes mediate the effective killing of both cancer stem cells and noncancer stem cells in vitro and in vivo. Enhanced treatment of both tumor cell populations results in an improved impairment of secondary tumor formation in vivo compared with treatment by unmodified chemotherapeutics. On the basis of these results, nanodiamond-mediated drug delivery may serve as a powerful method for overcoming chemoresistance in cancer stem cells and markedly improving overall treatment against hepatic cancers.

Epirubicin-adsorbed nanodiamonds kill chemoresistant hepatic cancer stem cells.

Schistosomiasis is the most important human helminth infection due to its impact on public health. Worldwide, schistosomiasis is estimated to infect at least 200 million individuals while 700 million are at risk. The clinical manifestations are chronic and significantly decrease an individual's quality of life. Infected individuals suffer from long-term organ pathologies including fibrosis which eventually leads to organ failure. The development of a vaccine against this parasitic disease would contribute to a long-lasting decrease in disease spectrum and transmission. Our group has chosen to target Schistosoma mansoni Cathepsin B as a prospective vaccine candidate. The recombinant protein was tested in the presence of synthetic oligodeoxynucleotides containing unmethylated CpG dinucleotides, which are Toll-like receptor 9 agonists known to stimulate a Th1 response. This formulation conferred a 59% decrease in worm burden as well as a reduction in egg burden. Hepatic egg burden and intestinal egg burden were decreased by 56% and 54% respectively. Immunizations with the formulation elicited robust production of Sm-Cathepsin B specific antibodies, both IgG1 and IgG2c but with the latter predominating. Furthermore, splenocytes isolated from the immunized animals, compared to control animals, had increased secretion levels of key Th1 cytokines, IFN-γ and TNF-α, as well as the chemokine CCL5 when stimulated with recombinant Sm-Cathepsin B. These results highlight the potential of Sm-Cathepsin B/CpG as a vaccine candidate against schistosomiasis.

Evaluation of the immune response and protective efficacy of Schistosoma mansoni Cathepsin B in mice using CpG dinucleotides as adjuvant.

Protein-based biopharmaceuticals are generally produced as aqueous solutions and stored refrigerated to obtain sufficient shelf life. Alternatively, proteins may be freeze-dried in the presence of sugars to allow storage stability at ambient conditions for prolonged periods. However, to act as a stabilizer, these sugars should remain in the glassy state during storage. This requires a sufficiently high glass transition temperature (Tg). Furthermore, the sugars should be able to replace the hydrogen bonds between the protein and water during drying. Frequently used disaccharides are characterized by a relatively low Tg, rendering them sensitive to plasticizing effects of residual water, which strongly reduces the Tg values of the formulation. Larger sugars generally have higher Tgs, but it is assumed that these sugars are limited in their ability to interact with the protein due to steric hindrance. In this paper, the size and molecular flexibility of sugars was related to their ability to stabilize proteins. Four diverse proteins varying in size from 6 kDa to 540 kDa were freeze-dried in the presence of different sugars varying in size and molecular flexibility. Subsequently, the different samples were subjected to an accelerated stability test. Using protein specific assays and intrinsic fluorescence, stability of the proteins was monitored. It was found that the smallest sugar (disaccharide trehalose) best preserved the proteins, but also that the Tg of the formulations was only just high enough to maintain sufficient vitrification. When trehalose-based formulations are exposed to high relative humidities, water uptake by the product reduces the Tgs too much. In that respect, sugars with higher Tgs are desired. Addition of polysaccharide dextran 70 kDa to trehalose greatly increased the Tg of the formulation. Moreover, this combination also improved the stability of the proteins compared to dextran only formulations. The molecularly flexible oligosaccharide inulin 4 kDa provided better stabilization than the similarly sized but molecularly rigid oligosaccharide dextran 6 kDa. In conclusion, the results of this study indicate that size and molecular flexibility of sugars affect their ability to stabilize proteins. As long as they maintain vitrified, smaller and molecularly more flexible sugars are less affected by steric hindrance and thus better capable at stabilizing proteins.

Ammonium sulfate

anhydrous, Redi-Dri^™, ReagentPlus^®, ≥99.0%

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Peer Reviewed Papers

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Ammonium sulfate

anhydrous, Redi-Dri™, ReagentPlus®, ≥99.0%

Properties

grade

product line

assay

form

pH

mp

solubility

density

cation traces

SMILES string

InChI

InChI key

Description

General description

Application

Legal Information

Safety Information

Storage Class Code

WGK

Flash Point(F)

Flash Point(C)

Documentation

Certificate of Analysis

Certificate of Origin

More Documents

Quotes and Ordering

Frequently Asked Questions

How does Redi-Dri™ help keep salts and buffers free-flowing?

Are there any special storage conditions that must be maintained?

How long will material remain free-flowing after it is opened?

Peer Reviewed Papers

Technical Service

anhydrous, Redi-Dri^™, ReagentPlus^®, ≥99.0%

How does Redi-Dri^™ help keep salts and buffers free-flowing?