The Experts below are selected from a list of 114 Experts worldwide ranked by ideXlab platform

Zvi Selinger - One of the best experts on this subject based on the ideXlab platform.

  • Linearization of the Bradford Protein Assay Increases Its Sensitivity: Theoretical and Experimental Studies
    Analytical Biochemistry, 1996
    Co-Authors: Tsaffrir Zor, Zvi Selinger
    Abstract:

    Determination of microgram quantities of Protein in the Bradford Coomassie brilliant blue Assay is accomplished by measurement of absorbance at 590 nm. However, as intrinsic nonlinearity compromises the sensitivity and accuracy of this method. It is shown that under standard Assay conditions, the ratio of the absorbances, 590 nm over 450 nm, is strictly linear with Protein concentration. This simple procedure increases the accuracy and improves the sensitivity of the Assay about 10-fold, permitting quantitation down to 50 ng of bovine serum albumin. Furthermore, Protein Assay in presence of up to 35-fold weight excess of sodium dodecyl sulfate (detergent) over bovine serum albumin (Protein) can be performed. A linear equation that perfectly fits the experimental data is provided on the basis of mass action and Beer's law.

Salvador Navarro - One of the best experts on this subject based on the ideXlab platform.

  • an improved Bradford Protein Assay for collagen Proteins
    Clinica Chimica Acta, 1993
    Co-Authors: Josemanuel Lopez, Santiago Imperial, Rodrigo Valderrama, Salvador Navarro
    Abstract:

    A modification of the Protein determination method of Bradford adapted for collagen-rich samples is described. The use of Coomassie-based Protein determination methods is limited by the great variation in colour yield obtained for different Proteins. This is especially important in samples containing significant amounts of collagen where direct application of the methods of Lowry and Bradford results in underestimated values. Addition of small amounts of sodium dodecyl sulphate (SDS) (0.0035%) to the diluted solutions of Coomassie Brilliant Blue G used as dye reagent in the Bradford colorimetric Assay caused a 4-fold increase in the colour response of three collagen Proteins (Col I, III and IV) and a decrease in absorbance for various non-collagen Proteins. The presence of SDS in the reagent did not result in a significant metachromatic shift of the collagen-dye complexes. This simple modification in the preparation of the reagent for the Bradford Assay allows similar response curves to be obtained for collagen and non-collagen Proteins, making the modified Assay of potential use for Protein determination in collagen-rich samples such as pancreatic extracts.

Tsaffrir Zor - One of the best experts on this subject based on the ideXlab platform.

  • linearization of the Bradford Protein Assay
    Journal of Visualized Experiments, 2010
    Co-Authors: Orna Ernst, Tsaffrir Zor
    Abstract:

    Determination of microgram quantities of Protein in the Bradford Coomassie brilliant blue Assay is accomplished by measurement of absorbance at 590 nm. This most common Assay enables rapid and simple Protein quantification in cell lysates, cellular fractions, or recombinant Protein samples, for the purpose of normalization of biochemical measurements. However, an intrinsic nonlinearity compromises the sensitivity and accuracy of this method. It is shown that under standard Assay conditions, the ratio of the absorbance measurements at 590 nm and 450 nm is strictly linear with Protein concentration. This simple procedure increases the accuracy and improves the sensitivity of the Assay about 10-fold, permitting quantification down to 50 ng of bovine serum albumin. Furthermore, the interference commonly introduced by detergents that are used to create the cell lysates is greatly reduced by the new protocol. A linear equation developed on the basis of mass action and Beer's law perfectly fits the experimental data.

  • Linearization of the Bradford Protein Assay Increases Its Sensitivity: Theoretical and Experimental Studies
    Analytical Biochemistry, 1996
    Co-Authors: Tsaffrir Zor, Zvi Selinger
    Abstract:

    Determination of microgram quantities of Protein in the Bradford Coomassie brilliant blue Assay is accomplished by measurement of absorbance at 590 nm. However, as intrinsic nonlinearity compromises the sensitivity and accuracy of this method. It is shown that under standard Assay conditions, the ratio of the absorbances, 590 nm over 450 nm, is strictly linear with Protein concentration. This simple procedure increases the accuracy and improves the sensitivity of the Assay about 10-fold, permitting quantitation down to 50 ng of bovine serum albumin. Furthermore, Protein Assay in presence of up to 35-fold weight excess of sodium dodecyl sulfate (detergent) over bovine serum albumin (Protein) can be performed. A linear equation that perfectly fits the experimental data is provided on the basis of mass action and Beer's law.

Josemanuel Lopez - One of the best experts on this subject based on the ideXlab platform.

  • an improved Bradford Protein Assay for collagen Proteins
    Clinica Chimica Acta, 1993
    Co-Authors: Josemanuel Lopez, Santiago Imperial, Rodrigo Valderrama, Salvador Navarro
    Abstract:

    A modification of the Protein determination method of Bradford adapted for collagen-rich samples is described. The use of Coomassie-based Protein determination methods is limited by the great variation in colour yield obtained for different Proteins. This is especially important in samples containing significant amounts of collagen where direct application of the methods of Lowry and Bradford results in underestimated values. Addition of small amounts of sodium dodecyl sulphate (SDS) (0.0035%) to the diluted solutions of Coomassie Brilliant Blue G used as dye reagent in the Bradford colorimetric Assay caused a 4-fold increase in the colour response of three collagen Proteins (Col I, III and IV) and a decrease in absorbance for various non-collagen Proteins. The presence of SDS in the reagent did not result in a significant metachromatic shift of the collagen-dye complexes. This simple modification in the preparation of the reagent for the Bradford Assay allows similar response curves to be obtained for collagen and non-collagen Proteins, making the modified Assay of potential use for Protein determination in collagen-rich samples such as pancreatic extracts.

Amir Landarani Isfahani - One of the best experts on this subject based on the ideXlab platform.

  • covalent attachment of xylanase on functionalized magnetic nanoparticles and determination of its activity and stability
    Chemical Engineering Journal, 2015
    Co-Authors: Asieh Soozanipour, Asghar Taherikafrani, Amir Landarani Isfahani
    Abstract:

    Abstract The covalent binding of xylanase to silica-coated modified magnetite nanoparticles via cyanuric chloride activation was investigated. The structure, size, and magnetic properties of the support and immobilized xylanase were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectra (FTIR), thermo-gravimetric analysis (TGA) and vibrating sample magnetometer (VSM) analysis. The TEM images showed that the xylanase immobilized on functionalized magnetic nanoparticles (xylanase-MNPs) possessed three dimensional core–shell structures with an average diameter of ∼9 nm. The FTIR and XPS results demonstrated the successful immobilization of xylanase on functionalized MNPs. Results from Bradford Protein Assay and TGA indicated that xylanase was covalently attached to the surface of modified magnetic nanoparticles with immobilization yield of 280 mg enzyme/g MNPs. The VSM analysis revealed that Fe 3 O 4 , Fe 3 O 4 @SiO 2 and xylanase-MNPs had high saturation magnetization of 69.4, 63.84 and 46.56 emu/g, respectively. Enzymatic activity, reusability, thermo-stability, pH-stability, and storage stability of the immobilized xylanase were found significantly superior to those of the free one. The xylanase-MNPs exhibited maximal catalytic activity at pH 6.5 and 60 °C and the immobilized enzymes were found to keep as high as 80% of the activity of free ones. Notably, xylanase-MNPs showed quite impressive stability, even after 9 reaction cycles, it could still retain about 65% of the initial activity. The measurement of Michaelis–Menten parameters ( K m and v max ) also revealed the considerable improvement of immobilized enzyme. The results suggested that xylanase-MNPs could be used in an interesting range of application allowing both using in broader temperature and pH ranges, facilitating long-term storage, while permitting magnetic recovery of the enzyme for reuse or purification of the product.