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Showing papers on "Bradford protein assay published in 1987"


Journal ArticleDOI
TL;DR: In this article, the authors compared the results obtained by the CO- and the dithionite (DT)-difference methods for total cytochrome P-450 in four laboratories.
Abstract: Assay conditions in determining total cytochrome P-450 in four laboratories were compared. Although the determination was derived from the original Omura and Sato method in each laboratory, the four standard protocols differed slightly, resulting in considerable differences in the results. Since the cytochrome P-450 content is usually expressed per mg protein, the protein assay conditions were evaluated as well. Furthermore, we compared the cytochrome P-450 values obtained by the CO- and the dithionite (DT)-difference methods. The effect of a number of variables in the assay was investigated. The influence of the storage temperature of the microsomes was ascertained as well as effects of the gassing time with CO and the time between addition of dithionite, CO-gassing and the recording of the difference spectra. After evaluating these variables a standard operation procedure was established. Using this procedure the interlaboratory coefficient of variation for total cytochrome P-450 was 4.8%, a value which was comparable to the intralaboratory coefficients of variation. The final results also show that the millimolar extinction coefficient for the DT-difference method is higher than for the CO-difference method.

202 citations


Journal ArticleDOI
TL;DR: A simple, fast protein assay which utilizes the affinity of colloidal gold for proteins is described, which is sensitive at the 20-ng level when a visible light spectrophotometer is used to measure absorbance.

121 citations


Journal ArticleDOI
TL;DR: A procedure was developed for the quantitation of solubilized proteins using the Bradford assay in the presence of glucopyranoside detergents, which was as rapid and convenient as the original Bradford protein assay.

116 citations


Journal ArticleDOI
TL;DR: A simple assay for small amounts of protein that is insensitive to sodium dodecyl sulfate (SDS) or many common interfering substances including Tris and reducing sugars, which is particularly useful in the analysis of protein content of samples prior to SDS electrophoresis.

110 citations


Journal ArticleDOI
TL;DR: The dye-binding method is unsuitable for protein assay in phenol- and phenolase-rich plant tissues because it gives grossly erroneous results when the homogenizing media differed.

36 citations


Journal ArticleDOI
TL;DR: Lowry blue interacts with auramine O, giving a large increase in A500 nm and a 40-fold amplification of the LB signal and the product is also fluorescent and could be exploited in a protein assay.

32 citations


Patent
22 Jun 1987
TL;DR: In this paper, a method for quantita-tively determining protein, comprising the steps of:a) providing a sample of the protein in an aqueous medium; b) providing an aqous medium having a pH in excess of 12 and comprising i) a cupric salt and a pyridyl-azo dye; or ii) a preformed cupric-pyridisylazo dye complex; c) combining the aaqous mediums of a) and b) thereby providing a color having an intensity which is inversely proportional to the amount of unre
Abstract: -i-ANALYTICAL METHOD AND ELEMENT FOR PROTEIN ASSAY Abstract of the Disclosure There is disclosed a method for quantita-tively determining protein, comprising the steps of:a) providing a sample of the protein in an aqueous medium; b) providing an aqueous medium having a pH in excess of 12 and comprising i) a cupric salt and a pyridyl-azo dye; or ii) a preformed cupric-pyridylazo dye complex; c) combining the aqueous mediums of a) and b) thereby providing a color having an intensity which is inversely proportional to the amount of unreacted dye present in the combined mediums; and d) determining the quantity of protein present in the sample colorimetrically. The method can be used with a multilayer dry analytical element.

12 citations


Patent
27 May 1987
TL;DR: In this paper, a quantitative assay for an analyte which comprises contacting a sample containing a analyte with a solid phase support to immobilize said analyte, following by indirectly quantitating the presence of bound analyte by titrating the unoccupied binding sites with a titrating protein which is detectably labeled.
Abstract: The invention relates to a quantitative assay for an analyte which comprises contacting a sample containing an analyte with a solid phase support to immobilize said analyte, following by indirectly quantitating the presence of bound analyte by titrating the unoccupied binding sites with a titrating protein which is detectably labeled.

5 citations


Book ChapterDOI
01 Jan 1987
TL;DR: The commonly used methods for determining total protein have been described elsewhere by Lowry et al. (1951), Warburg and Christian (1941), and Bradford (1976) and have recently been reviewed in detail by Petersen (1983).
Abstract: While standardized protein assays are used in nearly every laboratory, the limitations of many of these assays are frequently overlooked. It is important that an investigator realize that most protein assays are relative and are based on the measurement of particular amino acid residues and/or peptide bonds. The estimation of protein in different assays will therefore depend on the abundance of those amino acids in the protein sample. Because different protein assays may detect different amino acid residues, totally different estimations of protein content may be obtained for the same sample when different methodologies are used. It may therefore be necessary to use more than one protein assay to determine which is optimal for your needs. Table 3.1 summarizes amino acid residues or other chemical bases for protein estimation by different protein assay methods. The commonly used methods for determining total protein have been described elsewhere by Lowry et al. (1951), Warburg and Christian (1941), and Bradford (1976) and have recently been reviewed in detail by Petersen (1983). This latter review also presents a detailed list of chemicals including buffers and detergents that interfere with some of these protein assays.

1 citations


Journal ArticleDOI
TL;DR: The amount of albumin adsorbed to three dental crown and bridge alloys (high and low-gold content and silver-palladium), platinum, silver, and stainless steel was quantitated for the as-immersed conditions as well as with anodic and cathodic charge transfers in artifical saliva at a pH = 6.8.
Abstract: The amount of albumin adsorbed to three dental crown and bridge alloys (high- and low-gold content and silver-palladium), platinum, silver, and stainless steel was quantitated for the as-immersed conditions as well as with anodic and cathodic charge transfers in artifical saliva at a pH = 6.8. A methanolchloroform technique was utilized prior to protein assay which precipitated protein by phase separation. Amido black staining of protein on nitrocellulose filter paper was evaluated for optical density and compared to a standard curve of known quantities of protein. Cathodic charges decreased the quantity of adsorbed protein while anodic charges both increased and decreased adsorbed protein depending upon metal or alloy. Quantities adsorbed ranged from 0.5 to 8 μg/cm2. Interaction of positive oxidized species with the excess negative charges of the albumin molecules is thought to have increased protein adsorption. Formation of corrosion products with inorganic conponents is thought to have masked positive charges from protein thereby decreasing adsorption.

1 citations