Highly purified agarose as stacking gel in sodium dodecyl sulphate/polyacrylamide-gel electrophoresis.
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ABSTRACT: A modified sodium dodecyl sulphage/polyacrylamide-gel-electrophoretic method is described that utilizes highly purified agarose as stacking gel. The same electrophoretic resolution of different marker proteins is found as when polyacrylamide is used as stacking gel, but the background staining seen when polyacrylamide is used as stacking gel is decreased.
Project description:The estimate of the molecular weight of leghaemoglobin by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis is about 20% too low. This is due to an anomalously high limiting relative mobility. Leghaemoglobin binds 1.4 g of sodium dodecyl sulphate/g of protein with a concomitant decrease in the helical content from 71-72% to 49-51%.
Project description:Bartonella species can be differentiated by microimmunofluorescence assay, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and immunoblotting with murine polyclonal antisera to Bartonella henselae, B. quintana, B. elizabethae, and B. bacilliformis. A pairwise comparison on the basis of SDS-PAGE protein profiles demonstrated similarity values for proteins of different Bartonella species ranging from 28.6 to 86.4%. Antigenic relationships revealed by immunoblotting with murine antisera were equivalent to those of proteins observed by SDS-PAGE. A dendrogram obtained on the basis of protein bands of SDS-polyacrylamide gels showed that Bartonella species could be divided into three groups. B. bacilliformis was distinct from all other Bartonella species; B. grahamii, B. taylorii, B. doshiae, and B. vinsonii formed a cluster, as did B. henselae, B. quintana, B. elizabethae, and B. clarridgeiae. These relationships were consistent with those revealed by parsimony trees derived from 16S rRNA and gltA gene sequencing. SDS-PAGE analysis showed that 120-, 104-, 85-, 71-, 54-, 47-, 40-, 33-, 30-, and 19-kDa proteins were present in all species, with the 54-kDa protein being the most dominant. Proteins with a molecular mass of less than 54 kDa allow the differentiation of species and are a possible target for future species-specific antibodies and antigens.
Project description:A simple method is described for dodecyl sulphate/polyacrylamide-gel electrophoresis of pH- and temperature-labile biological intermediates. The method is based on a catalyst system that works at temperatures of 2--4 degrees C and pH values of 2--4 and an appropriate buffer system containing Li+ or Tris [CH2OH--C(CH2OH)2--NH3+] instead of Na+. This system does not lead to the precipitation of 1% dodecyl sulphate.
Project description:In this technical note, we design and fabricate a novel rotary valve and demonstrate its feasibility for performing isoelectric focusing and simultaneous fractionation of proteins, followed by sodium dodecyl-polyacrylamide gel electrophoresis. The valve has two positions. In one position, the valve routes a series of capillary loops together into a single capillary tube where capillary isoelectric focusing (CIEF) is performed. By switching the valve to another position, the CIEF-resolved proteins in all capillary loops are isolated simultaneously, and samples in the loops are removed and collected in vials. After the collected samples are briefly processed, they are separated via sodium dodecyl-polyacrylamide gel electrophoresis (SDS-PAGE, the second-D separation) on either a capillary gel electrophoresis instrument or a slab-gel system. The detailed valve configuration is illustrated, and the experimental conditions and operation protocols are discussed.
Project description:Primers were designed from 16S rRNA sequences of Prevotella intermedia sensu stricto and Prevotella nigrescens and were used to discriminate these two species by PCR. The results were compared with those from the PCR technique using primers designed from arbitrarily primed PCR products by Guillot and Mouton (E. Guillot and C. Mouton, J. Clin. Microbiol. 35:1876-1882, 1997). The specificities of both assays were studied by using P. intermedia ATCC 25611, P. nigrescens ATCC 33563, 174 clinical isolates of P. intermedia sensu lato, and 59 reference strains and 58 clinical isolates of other Prevotella species and/or common oral flora. In addition, the usefulness and reliability of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in the differentiation of the two species were examined by comparing the results with those from PCR assays. The controversial lipase test for distinguishing these species was also carried out. Unambiguous differentiation was made by both PCR assays, and the results matched each other. The SDS-PAGE assay was found to misidentify a few strains tested, compared with the results of PCR assays. The lipase test was positive for both species, including the reference strains of P. intermedia and P. nigrescens. We conclude that both PCR assays are simple, rapid, reliable, and specific methods which could be used in clinical studies and that the lipase test is not valuable in the differentiation. The reliable discrimination of the two species by SDS-PAGE is questionable.
Project description:Inositol 1,4,5-trisphosphate (InsP3) 3-kinase catalyses the ATP-dependent phosphorylation of InsP3 to inositol 1,3,4,5-tetrakisphosphate (InsP4). A method is presented for the rapid purification of InsP3 3-kinase from bovine brain by calmodulin (CaM)-Sepharose affinity chromatography. Maximal activation of the purified InsP3 3-kinase by Ca2+/CaM was 6-7-fold as compared with the activity measured in the presence of EGTA (1 mM) and 10 microM-InsP3. At 10 microM-InsP3 and 0.1 mM free Ca2+, half-maximal activation required about 2 nM-CaM. The mechanism of activation by CaM appeared to be an increase in the maximal velocity of the enzyme without a substantial change in the Km for InsP3. Further purification was achieved by phosphocellulose chromatography eluted with ATP. Specific activity of the purified enzyme at 37 degrees C and 10 microM-InsP3 was 10-20 mumol/min per mg. The apparent Mr of the enzyme, determined by f.p.l.c.-gel filtration, was estimated as about 44,000. The purified InsP3 3-kinase was subjected to SDS/10%-polyacrylamide-gel electrophoresis. InsP3 3-kinase activity was associated with three silver-stained bands, which migrated with apparent Mr values of approx. 52,000, 38,000 and 35,000.
Project description:Agarose and polyacrylamide gel electrophoresis systems for the molecular mass-dependent separation of hyaluronan (HA) in the size range of approximately 5-500 kDa were investigated. For agarose-based systems, the suitability of different agarose types, agarose concentrations, and buffer systems was determined. Using chemoenzymatically synthesized HA standards of low polydispersity, the molecular mass range was determined for each gel composition over which the relationship between HA mobility and logarithm of the molecular mass was linear. Excellent linear calibration was obtained for HA molecular mass as low as approximately 9 kDa in agarose gels. For higher resolution separation, and for extension to molecular masses as low as approximately 5 kDa, gradient polyacrylamide gels were superior. Densitometric scanning of stained gels allowed analysis of the range of molecular masses present in a sample as well as calculation of weight-average and number-average values. The methods were validated for polydisperse HA samples with viscosity-average molecular masses of 112, 59, 37, and 22 kDa at sample loads of 0.5 μg (for polyacrylamide) to 2.5 μg (for agarose). Use of the methods for electrophoretic mobility shift assays was demonstrated for binding of the HA-binding region of aggrecan (recombinant human aggrecan G1-IGD-G2 domains) to a 150-kDa HA standard.
Project description:Brush-border membranes were isolated from the rat small intestine and then treated with sodium dodecyl sulphate under non-reducing conditions at room temperature. Analysis of the solubilized components by polyacrylamide-gel electrophoresis identified three major glycoproteins that co-migrate with glucoamylase-maltase-sucrase, lactase and isomaltase-maltase-sucrase activities. High activities of alkaline phosphatase and trehalase were detectable, but they could not be attributed to distinct co-migrating protein bands. Analysis of mucosa from the distal small intestine by the same methods showed a pattern of bands different from that obtained with the proximal intestine, which appeared to correlate with the relative deficiency of some of the enzymes in the distal region.
Project description:Circular RNAs are garnering increasing interest as potential regulatory RNAs and a format for gene expression. The characterization of circular RNA using analytical techniques commonly employed in the literature, such as gel electrophoresis, can, under differing conditions, yield different results when attempting to distinguish circular RNA from linear RNA of similar molecular weights. Here, we describe circular RNA migration in different conditions, analyzed by gel electrophoresis and high-performance liquid chromatography (HPLC). We characterize key parameters that affect the migration pattern of circular RNA in gel electrophoresis systems, which include gel type, electrophoresis time, sample buffer composition, and voltage. Finally, we demonstrate the utility of orthogonal analytical tests for circular RNA that take advantage of its covalently closed structure to further distinguish circular RNA from linear RNA following in vitro synthesis.
Project description:BackgroundSulfotransferases are a large group of enzymes that regulate the biological activity or availability of a wide spectrum of substrates through sulfation with the sulfur donor 3'-phosphoadenosine-5'-phosphosulfate (PAPS). These enzymes are known to be difficult to assay. A convenient assay is needed in order to better understand these enzymes.ResultsA universal sulfotransferase assay method based on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) is described. This assay has been successfully applied to substrates as small as alpha-naphthol and as big as proteoglycans. As examples, we present the assays for recombinant human CHST4, TPST1, CHST3 and HS6ST1. In order to assess whether a small molecule can be applicable to this type of assay, a method to estimate the relative mobility of a molecule to PAPS is also presented. The estimated relative mobilities of various sulfated small molecules generated by SULT1A1, SULT1E1, SULT2A1 and CHST4 are in the range of +/- 0.2 of the actual relative mobilities.ConclusionThe versatility of the current method comes from the ability that SDS-PAGE can separate proteins and small molecules according to different parameters. While mobilities of proteins during SDS-PAGE are inversely related to their sizes, mobilities of small molecules are positively related to their charge/mass ratios. The predicted relative mobility of a product to PAPS is a good indicator of whether a sulfotransferase can be assayed with SDS-PAGE. Because phosphorylation is most similar to sulfation in chemistry, the method is likely to be applicable to kinases as well.