Showing papers on "Bradford protein assay published in 1998"

Comparison of Different Methods of Cell Lysis and Protein Measurements in Clostridium perfringens: Application to the Cell Volume Determination

Abstract: Four cell lysis methods (NaOH-SDS solubilization, French press treatment, sonication, mutanolysin treatment) and three methods of protein assays (Lowry, Bradford, Pierce) were studied for their applicability to determination of cell volume in Clostridium perfringens NCTC 8798 cell suspensions. Protein contents were higher after a mechanical disruption of the cells than with the other techniques of lysis. The lowest concentrations of protein were obtained with the Bradford procedure. With each of the three protein assay methods, Clostridium perfringens NCTC 8798 protein cell contents were 45% to 58% of protein. Other factors possibly involved in variations of the intracellular volume measurements were examined. A control of the level of protein concentration in the test sample and the type of silicone oil used for the centrifugation were of prime importance during sample preparation. Under our conditions, an intracellular volume of 4 μl/(mg of protein) was routinely found for Clostridium perfringens NCTC 8798.

Solventless protein assay standard

Abstract: A method for preparing a solventless protein standard is disclosed in which a solventless dye indicator and a predetermined amount of solventless protein are placed in an appropriate receptacle such as the well of a multiwell plate. This results in a solventless protein standard in which the solventless protein and the solventless dye are contained within the same receptacle. When an appropriate solvent is added to the receptacle, the protein and dye react together to produce a color change which is detectable, and which can be used as a standard for a protein assay using that dye. Also claimed is the solventless protein assay standard produced by the process.

Elastic Light - scattering of Protein - Chrome Azurol S Complex and Its Preliminary Analytical Application

Abstract: In the medium of citric acid - NaOH buffer (pH 3. 5), proteins may combine with chrome azurol S (CAS) by intermolecular forces (mainly by electrostatic force) to form macromolecular ion - association complexes, causing an elastic light - scattering signal with a maximum wavelength of about 370 nm. Based upon this,a new method for the determination of serum albumin with a detection limit of 0. 02μ g·mL-1 was proposed. Its calibration curve is linear over the range of 0-1.0μg·mL-1. The sensitivity of this method is fifty - fold higher than that of the Coomassie brilliant blue protein assay. The scattering spectra of this system were measured using an ordinary spectrofluorophotometer. Influence of experimental conditions,such as pH,ionic strength,and concentration of CAS,on the intensity of light- scattering was studied. Effects of surfactants (cationic, anionic, and nonionic), amino acids, and metal ions on the combination of CAS with protein were also investigated. This method has been used for the determination of urinary protein with good results.

A micromethod for protein assay using a light microscope.

Abstract: A micromethod which utilizes a protein-dye binding reaction on an acetate membrane and a light microscope with an automatic exposure instrument has been developed for measuring small amounts of protein from limited biological materials. After discoidal cellulose acetate membranes (2.0 mm diameter), which absorbed 0.5 microliter of protein solution containing 0.2-2.0 micrograms of protein, were stained with Coomassie Brilliant Blue G-250, they were examined by a light microscope with an automatic exposure instrument. A linear relation was confirmed between the intensity of dye binding to protein and exposure time under specific optical conditions.