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The isoelectric point (pI), sometimes abbreviated to IEP, is the pH at which a particular molecule or surface carries no net electrical charge.. Amphoteric molecules called zwitterions contain both positive and negative charges depending on the functional groups present in the molecule. The net charge on the molecule is affected by pH of their surrounding environment and can become more positively or negatively charged due to the loss or gain of protons (H+). The pI is the pH value at which the molecule carries no electrical charge or the negative and positive charges are equal.. Surfaces naturally charge to form a double layer. In the common case when the surface charge-determining ions are H+/OH-, the net surface charge is affected by the pH of the liquid in which the solid is submerged. Again, the pI is the pH value of the solution at which the surfaces carries no net charge.. The pI value can affect the solubility of a molecule at a given pH. Such molecules have minimum solubility in water ...
The pH at which a protein carries no net charge. Below the isoelectric point proteins carry a net positive charge; above it a net negative charge. Due to a preponderance of weakly acid residues in almost all proteins, they are nearly all…
pI profiles across HC CDR3 regions of NZM2410-derived ANAs and non-ANAs. The mean pI value (isoelectric point) at each HC CDR3 position (from H95 to H100a) was
Introduction. Determination of isoelectric point of protein (casein). Introduction: Casein is a globular colloidal protein. Globular proteins are hydrophobic proteins which in certain external condition are soluble in eater. The ph at which the protein is electrically neutral is known as the isoelectric point. A globular protein such as a casein becomes increasingly insoluble as it approaches its isoelectric point. Objectives The object of this experiment is to determine the isoelectric point of casein (protein), which can be precipitated from the solution. Apparatus 9 test tubes pipettes - 1ml - 5ml - 10ml colorimeter Materials Distilled water Acetic acid - 0.01 M - 0.1M - 1.0 M casein - 0.5g/1 in 0.1 M sodium acetate Method 1. The calorimeter is switched ON to allow it to warm up. 2. In order to distinguish between the different acidity levels contained in each test tube, the 9 test tubes were labelled from 1-9. This is important because all solution are a similar colour. 3. Following the ...
The isoelectric point (pI) of a protein is of practical importance in many separation procedures, both analytical and preparative. The pI is defined as the pH where the net charge of the protein is zero. Therefore, by plotting the mobilities of the proteins against pH, the intercept at zero mobility should yield the pI value. Isoelectric points have traditionally been determined by isoelectric focusing. In this paper, the potential of capillary electrophoresis as an alternative technique for the determination of pI values of both acidic and basic proteins was investigated. The problem commonly encountered with adsorption of the positively charged proteins with the unprotonated silanol groups of the fused-silica wall is solved by applying a dynamic coating of a polycationic reagent to the wall. The advantages of this technique of determining the pI values are simplicity, speed and minimal sample requirement ...
using the SVM model default > pI <- pISVMpeptide(sequence = "AGAAPYVQAFDSLLAGPVAE", model="default") > #the result will be... > pI [1] 4.015568[1] ---------------------------------------------------------------------------------------- > # using the SVM model heller > pI <- pISVMpeptide (sequence = "AGAAPYVQAFDSLLAGPVAE", model="heller") > #the result will be... > pI[2] [1] 4.178931 ---------------------------------------------------------------------------------------- > # using the SVM model branca > pI <- pISVMpeptide (sequence = "AGAAPYVQAFDSLLAGPVAE", model="branca") > #The result will be... > pI [1] 4.049737 ---------------------------------------------------------------------------------------- Most of the tools allow to compute the isoelectric point (example above) to individual sequences. However, to predict the isoelectric point of a list of peptides/proteins (for example, a short list of sequences contained in a file) the following option could be used: ...
compute the isoelectric point pi of each of the given amino acidsa glycineb glutamic acidc, Hire Biology Expert, Ask Academics Expert, Assignment Help, Homework Help, Textbooks Solutions
The data on approximate values of isoelectric point (pI) of peptides obtained during their fractionation by isoelectric focusing can be successfully used for the creation of the pKa scale for amino ac
A plurality of particles of from about 5 nm to 100 μm possessing predetermined isoelectric points in the pH range from about 2.5 to 11 is used in a method of detection of a plurality of analytes, wherein the isoelectric particles of each isoelectric point further contain a label and a member of a binding pair capable of interacting with a selected analyte. The particles that formed specific binding pairs are recovered and separated by isoelectric focusing, followed by the detection of the labels associated with the particles. A flow cytometer may be used as a detector of the isoelectric particles.
0031]Additional parameters, however, are also used to control the viscosity of the slurry composition. For example, the temperature and pH of the slurry composition, the amount of mixing the slurry composition is subjected to, and the final concentration of the self-aggregating protein in the final slurry composition are additional factors influencing the final viscosity thereof. The pH of the aqueous slurry must be monitored in order to ensure that it remains in an aqueous state. It is within the knowledge of the skilled artisan to select an appropriate pH based on the isoelectric point of the raw material, e.g., based on the isoelectric point of the self-aggregating protein contained therein. For example, the pH of the slurry should be maintained no less than 0.3 pH units away from the isoelectric point of the raw material. In the case of limed bovine skin type I collagen in which the isoelectric point is 4.2, it is preferred that the pH of the aqueous slurry be maintained in the range of ...
An electroconductive powder composition of antimony-containing tin oxide with an outer layer of hydrous metal oxide having an isoelectric point in the range from about 5 to 9.
James McIninch (james at gatech.edu) wrote: : Im looking for a utility, or code fragment, that estimates the isoelectric : points of proteins from IUPAC (single-character) amino acid sequences. : I tried looking for the protein in all of the different protein databases : available for the net to see if I couldnt find a reference to the IP there, : but no luck. I have the aa sequence, now all I need is the code (I could : always write it, but no need to reinvent the wheel). If the protein is in SwissProt, then the ExPASy WWW server will calculate the predicted pI and molecular weight for you. Most commercial packages have a pI calculator buried somewhere in the package. Keith Robison Harvard University Department of Cellular and Developmental Biology Department of Genetics / HHMI robison at mito.harvard.edu ...
in Proceedings of the Middel European Buiatrics Congress, 1998 (1998, May 21). Proteins secreted by the placenta, when detected in the peripheral circulation of the mother, can be useful indicators of both pregnancy and feto-trophoblast well-being (1-3). In 1982, Butler et al. (4 ... [more ▼]. Proteins secreted by the placenta, when detected in the peripheral circulation of the mother, can be useful indicators of both pregnancy and feto-trophoblast well-being (1-3). In 1982, Butler et al. (4) isolated two pregnancy-specific proteins (PSPA and PSPB) from bovine placental membranes. PSPA was identified as a-fetoprotein which is not strictly limited to pregnancy, while PSPB was confirmed as placentas and pregnancys specific (5). PSPB was characterized as a glycoprotein showing relative molecular masses (Mr) between 47 and 53 kDa and presenting different isoelectric points (from 4.0 to 4.4). The Mr of PSPB was similar to the Mr of the molecule isolated by Laster in 1977 (6). In 1991, Zoli et al. ...
Isoelectric Focusing (IEF) can be described as an ingenious process for simultaneous concentration and separation of proteins. IEF employs a pH gradient formed by small amphoteric molecules (called ampholytes) to resolve proteins according to their different pI values (pI = isoelectric point). IEF is an end point method - when the electrophoretic run is completed proteins will appear as separate, sharp zones, in the order of their isoelectric points.. For IEF, SERVA offers a comprehensive product line: ...
R. L. Prestidge, W. J. Koopman, J. C. Bennett, M. T. W. Hearn; Buffer electrofocusing of Interleukin I. Biosci Rep 1 April 1982; 2 (4): 241-246. doi: https://doi.org/10.1007/BF01136723. Download citation file:. ...
In this study, we used multiple functional assays to characterize NXT1, a protein that we identified based on its sequence relatedness to NTF2. The similarities of NXT1 and NTF2 include their amino acid identity (26% within a species), low molecular sizes (NTF2, 127 amino acids; NXT1, 140 amino acids), acidic isoelectric points (NTF2, 5.1; NXT1, 5.0), steady-state nuclear localization (45), interaction with the NPC (6, 31, 36), and direct binding to Ran (31, 34). However, NXT1 and NTF2 also have distinct properties that provide insights into their respective functions. NTF2 binds to Ran-GDP and mediates its import into the nucleus (38, 43,45), thereby functioning as a nuclear import factor. In contrast, NXT1 binds to Ran-GTP. The precise function of this interaction is unknown, but it clearly suggests a role in nuclear export. Indeed, using a permeabilized cell assay (16), we have shown here that NXT1 stimulates nuclear export of PKI. The logical interpretation of this result is that NXT1 ...
These last few decades, membranes and monoliths have been increasingly used as stationary phases for chromatography. Their fast mass transfer is mainly based on convection, which leads to reduced diffusion, which is usually observed in resins. Nevertheless, poor flow distribution, which causes inefficient binding, remains a major challenge for the development of both membrane and monolith devices. Moreover, the comparison of membranes and monoliths for biomolecule separation has been very poorly investigated. In this paper, the separation of two proteins, bovine serum albumin (BSA) and lactoferrin (LF), with similar sizes, but different isoelectric points, was investigated at a pH of 6.0 with a BSA-LF concentration ratio of 2/1 (2.00 mg·mL−1 BSA and 1.00 mg·mL−1 LF solution) using strong cation exchange membranes and monoliths packed in the same housing, as well as commercialized devices. The feeding flow rate was operated at 12.0 bed volume (BV)/min for all devices. Afterward, bound LF was eluted
Affinity purified Lotus tetragonolobus lectin (LTL) is isolated from lotus seeds and is composed of 240 amino acid residues. LTL is a glycoprotein consists of four subunits. This lectin has different isoelectric points of pH 7.3, 7.6, 7.9, 8.2 and a carbohydrate specificity toward α-fucose, it is most inhibited by L-fu
bes ,bes at pi5246.physik.uni-erlangen.de, wrote in message news:94oi30$eg5 at smc.vnet.net... , Hallo, , is it possible to use fractions for a label? , Show[Plot[x,{x,-1,1},DisplayFunction-,Identity], Ticks-,{ {-1,-3/4,-1/2,-1/4,1/4,1/2,3/4,1}, {-1,-3/4,-1/2,-1/4,1/4,1/2,3/4,1} } ,DisplayFunction-,$DisplayFunction] -- Paul Lutus www.arachnoid.com ...
           In this lecture, we were introduced to the concept of a new sensor called the impedance-based Biosensor. Biomolecules are originally charged and therefore there is a need to determine the charge of the molecule before using it on a sensor. Isoelectric Points, the pH at which a protein has a net 0 Charge, can now be looked up and used to determine whether the protein in mind is positively or negatively charged. The charge of the …
Results 51 eyes with different DR severities were imaged. More severe DR was significantly associated with lower PI after adjusting for logarithm of the minimum angle of resolution best-corrected visual acuity, hyperlipidaemia, diabetes type and ETDRS ring in a multivariate mixed linear model. Compared with the none-mild non-proliferative diabetic retinopathy (NPDR) group, the moderate-severe NPDR group had 2.7 lower PI (p=0.03) and proliferative DR group had 4.3 lower PI (p=0.003). All ETDRS zones except for the foveal centre showed inverse associations between PI and DR severity (p values,0.001 to 0.862). ...
Two-dimensional gel electrophoresis of nuclear phosphoproteins of Novikoff hepatoma and regenerating liver.: Two-dimensional polyacrylamide gel electrophoresis
Blood platelets are important components of hemostasis, contributing to healing of wounds by forming thrombi and to the initiation of repair processes. They are also involved, however, in the...
Samples of lyophilized ovalbumin were irradiated, under vacuum in a high energy, uniform field of γ-rays, to absorb dosages of 30, 60 and 100 electron volts/molecule (6.5, 13.0 and 21.7 × 106 rads). Solutions of the γ-irradiated ovalbumins were fractionated by promptly precipitating the radiation-denatured molecules at the isoelectric point of native ovalbumin, and by heating the neutral systems at 50°, 60° and 68°C and by precipitating the thermolabile constituents at the isoelectric point. Quantitative serologic tests on the solutions revealed that the irradiated ovalbumins had a dose-related loss of correspondence to native protein. Removal of the radiation-denatured and thermolabile constituents improved the correspondence of the supernatants to the native solutions. Supernatants from native and irradiated preparations, heated at 68°C, showed thermal damage serologically. Radiation-denatured and thermolabile proteins exhibited a low, essentially constant and doseunrelated serologic ...
A molecular Möbius strip that can flip between single-sided and double-sided modes has been synthesised by chemists in Poland without snapping the ring.. Lechoslaw Latos-Grazynski and his colleagues at the University of Wroclaw explain that for a molecule to be defined as aromatic it must exist as a near planar ring and have a pi electron system that allows for the free movement of electron pairs between alternating double and single bonds - the classic Hückel topology. Even rings that are twisted into a figure eight can have this topology. However, a molecule with a 180 degree twist has the Möbius topology and there is no distinction between the "upper and lower" pi electron cloud to give it the properties of aromaticity.. The team worked with an expanded porphyrin analogue - A,D-di-p-benzi[28]hexaphyrin(1.1.1.1.1.1) with a figure-of-eight shape having two phenylene six-membered carbon rings at the crossover point. Whether or not these rings are perpendicular or parallel dictates ...
View the Greek version 2-D gel electrophoresis Currently used in reference to the gel-based separation of proteins by their isoelectric point in one d...
CryoBioPhysica, creators of pISep buffers & pISep Software for separation of proteins by chromatofocusing with controllable external pH gradients.
Methods for microbial classification are not always capable of distinguishing between isolates at the species level. We have previously characterised four Ferroplasma isolates that were ,98.9% similar at the 16S rDNA level, the isolates showed marked phenotypic differences, and one isolate was borderline on the 70% species boundary from DNA-DNA similarity data. In this study we have used statistical comparisons of two-dimensional polyacylamide gel electrophoresis gels for classification of closely related isolates. From the protein profile similarities an un-rooted tree was constructed that was congruent with a tree derived from DNA-DNA similarities.. ...
Carcinoembryonic antigen (CEA) was purified from GW-39 human tumor xenografts in hamsters by immunoaffinity chromatography. Binding of the antigen to immobilized monoclonal antibody provided a high degree of purification of CEA in a single step. A recovery of 79% and a 750-fold purification were obtained. The purified CEA has a molecular size of 180 kilodaltons, an isoelectric point of 4.4, and a specific activity of 0.94. About 73% of the radiolabeled GW-39 CEA reacted with goat anti-CEA serum ...
alpha-Fetoprotein has been prepared from human fetal tissue by procedures utilizing DEAE-Sephadex, concanavalin A-Sepharose, and isoelectric focusing. A major and a minor component with isoelectric points of 4.7 and 5.3, respectively, have been isola
Dear will.i.am, We saw your piece in the Economist and were very excited to learn that you care about privacy as much as we do. At PI we expose government and corporate bad behaviours, we disrupt their plans, and identify a hopeful path forward. Thats why we very much agree with you that people need much more protection, transparency and control over their personal data. Cheers for: "I want to have it clearly explained in plain language who has access to my camera, to my photos, whos… ...
TY - JOUR. T1 - Chromatofocusing and isoelectric focusing in immobilized pH gradients compared for characterization of human hemoglobin variants. AU - Paleari, R.. AU - Arcelloni, C.. AU - Paroni, R.. AU - Fermo, I.. AU - Mosca, A.. PY - 1989. Y1 - 1989. N2 - We compared the performance of two highly resolving methods, chromatofocusing (CRF) and isoelectric focusing in immobilized pH gradients (IPGF), for the separation of human hemoglobin variants. Lysates containing 13 different hemoglobins, including variants of clinical and geographical importance, and four electrophoretically silent variants (Hb Brockton, Hb Cheverly, Hb Koln, and Hb Waco) were analyzed. Both techniques showed a good intrarun precision (CV = 0.87% for CRF, 0.27% for IPGF) and high and similar resolving power (0.010 pH units, with the pH gradients used in this work). The use of an ultranarrow IPGF range (pH 7.15-7.35; pH gradient = 0.019 pH/cm) allowed the resolution between Hb Brockton, Hb Koln, and Hb A. In some cases ...
OBJECTIVES. Isoelectric focusing (IEF) is a laboratory technique that allows to separate proteic molecules based on their isoelectric point. This technique, applied to cerebro spinal fluid (CSF) IgG, has been used to study human neurological diseases. CSF IgG concentration increases either with neurological diseases that alter the blood-brain barrier (BBB), increasing IgG access from the blood, or with neurological diseases that determine local activation of the immune system with intrathecal synthesis (IS) of IgG. To date, no studies on IEF of canine CSF have been performed. The purpose of this study was to investigate IgG patterns of distribution in CSF of dogs with several neurological diseases and to compare these data to CSF total protein concentrations for each dog.. MATERIALS. Twenty-four dogs have been included in the study. Sixteen dogs had spinal cord compression (SCC), 3 dogs had brain neoplasia (BN), 2 dogs had cerebellar abiotrophy (CA), 1 dog had steroid-responsive meningitis ...
Elastic and inelastic cross-sections for pion scattering on 12C at pion kinetic energy ranging from 50 to 260 MeV are computed using three independent methods of ?± -nucleus optical potential, the 3?-particle model of the nucleus, the equivalent local Kisslinger potential and the Laplacian one. Reasonable fits to the measured values are obtained for 12C without adjusting free parameters. The ability of these methods to account for elastic, inelastic, total and reaction cross-section data are somewhat similar. The Kisslinger-based local potential is the more suitable for describing the elastic and inelastic cross-sections of ?±-nucleus scattering. It seems that the 3?-particle model of 12C is not useful in the description of pion scattering on 12C at least in the ?-resonance region.
We used an atomic force microscope (AFM) with a modified tip to measure interaction forces between a silica microsphere and surfaces of quartz, calcite, and albite over a range of pH. Minima in the magnitude of electrostatic repulsion or attraction appeared near the point of zero charge (pHpzc) values for quartz (≈2.8), calcite (9.5), albite (2.6), and silica glass (3.5). We observed small, but significant, differences in pHpzc values for the (100), (101), and (011) faces of quartz. In order to correlate mineral surface charges with ionic characteristics and corresponding isoelectric points (pI) of amino acids, we immersed quartz and calcite in solutions of six amino acids. Quartz (pHpzc ≈ 2.8) tends to adsorb amino acids most strongly when pHpzc and pI differ significantly. Thus quartz adsorbs lysine (pI = 9.74) more strongly than amino acids with lower pI. In contrast, calcite (pHpzc = 9.5) adsorbs a variety of amino acids with a range of pI. Calcite thus represents a more plausible ...
6, is added to the egg whites before the denaturation process. Cream of tartar is an acid that is used to help stabilize and coagulate the proteins, which aids in a stronger protein network to trap air for the foam formation. Cream of tartar has a low pH to help bring the proteins near their isoelectric point to allow them to be denatured easier. The isoelectric point is a specific pH where a molecule, in this case protein, has no net electrical charge. The electrical charge on a protein would normally hold the protein together in its coiled clump.[10]. The cream of tartar also acts as a catalase affecting the sugar structure. Sugar/sucrose used in meringue is a crystal structure made up of glucose and fructose. Cream of tartar inverts the sugar during the baking process, meaning the sugar is split into two parts containing glucose and fructose. This prevents the sugar from recrystallizing and giving the meringue a gritty, undesirable texture.[11]. Sugar is the final ingredient that is used to ...
Dear Reader! I want to separate my target protein from other proteins in low concentration via native PAGE (poly acrylamide gel electrophoresis). What do I have to think about when planning the experiment? Where are the differences between native PAGE and SDS-PAGE? I heart that one has to calculate the isoelectric point. But how can I do this with a 300 aa-protein? (the sequence is known) Thank you for your answer! Thorsten Schmidt ...
Use a MicroRotofor cell to fractionate proteins in solution by isoelectric point (pI). Improve separation in downstream 2-D electrophoresis. Tenfold enrichment.
The pig endometrial arylsulphatase A was purified 3322-fold to a specific activity of 150 mumol/min per mg. The purification involved (NH4)2SO4 fractionation, chromatography on concanavalin A-Sepharose and DEAE-Sepharose, gel filtrations on Sephadex G-200 at pH 7.4 and 5, and a new preparative gel-electrophoresis technique. The homogeneous enzyme is a glycoprotein containing 20% carbohydrate. The purified enzyme has Mr about 120 000 and it contains subunits of Mr 63 000. The pig endometrial arylsulphatase A shows many properties in common with those of arylsulphatases A purified from other sources. The similarities include their low isoelectric points, the anomalous time-activity relationships, multi-pH optima, inhibition by SO3(2-), SO4(2-), phosphate ions, metal ions and nucleoside phosphates, pH- and ionic-strength-dependent polymerization and amino acid composition. ...
It is generally believed that intravenous application of cationic vectors is limited by the binding of abundant negatively charged serum components, which may cause rapid clearance of the therapeutic agent from the blood stream. However, previous studies show that systemic delivery of cationic gene vectors mediates specific and efficient transfection within the lung, mainly as a result of interaction of the vectors with serum proteins. Based on these findings, a novel and charge-density-controllable siRNA delivery system is developed to treat lung metastatic cancer by using cationic bovine serum albumin (CBSA) as the gene vector. By surface modification of BSA, CBSA with different isoelectric points (pI) is synthesized and the optimal cationization degree of CBSA is determined by considering the siRNA binding and delivery ability, as well as toxicity. The CBSA can form stable nanosized particles with siRNA and protect siRNA from degradation. CBSA also shows excellent abiliies to intracellularly ...
S-hydroxymethylglutathione dehydrogenase from Paecilomyces variotii No. 5 strain (NBRC 109023), isolated as a formaldehyde-degrading fungus, was purified by a procedure that included ammonium sulfate precipitation, DEAE-Sepharose and hydroxyapatite chromatography and isoelectrofocusing. Approximately 122-fold purification was achieved with a yield of 10.5%. The enzyme preparation was homogeneous as judged by sodium dodecyl polyacrylamide gel electrophoresis (SDS-PAGE). The molecular mass of the purified enzyme was estimated to be 49 kDa by SDS-PAGE and gel filtration, suggesting that it is a monomer. Enzyme activity was optimal at pH 8.0 and was stable in the range of pH 7.0-10. The optimum temperature for activity was 40°C and the enzyme was stable up to 40°C. The isoelectric point was pH 5.8. Substrate specificity was very high for formaldehyde. Besides formaldehyde, the only aldehyde or alcohol tested that served as a substrate was pyruvaldehyde. Enzyme activity was enhanced by several divalent
A scheme for PI(3,4,5)P3-mediated chemotaxis reversal by 8CPT-cAMP consists of three parts (Fig. 4). The basis is a PLC/PI(4,5)P2 polarity switch. In D. discoideum, PLC is regulated by the activating Gα2 and inhibitory Gα1, which, in a gradient of attractant or repellent, will determine the polarity of the PI(4,5)P2 gradient. The attractant cAMP shows predominant activation of PLC, leading to lower PI(4,5)P2 levels upgradient, while the repellent 8CPT-cAMP inhibits PLC, leading to higher PI(4,5)P2 levels upgradient. The resulting gradients of PI(4,5)P2 and colocalized PTEN mediate opposite gradients of PI(3,4,5)P3, leading to the localized polymerization of actin. The gradients of localized PTEN and PI3K are stabilized because PTEN accumulates at the site of its product PI(4,5)P2, whereas PI3K accumulates at sites of its effector, PI(3,4,5)P3-induced F-actin. This mutually spatial exclusion of PI3K and PTEN will result in symmetry breaking, by which small spatial differences in the underlying ...
The present invention provides a novel cellulase composition obtainable from Bacillus sp. CBS 669.93. A preferred cellulase has a calculated molecular weight of approximately 63 kD, a calculated isoelectric point of about 5 and a pH optimum on CMC of about 6 at 40 C. and 60 C.