Bradford protein assay

About: Bradford protein assay is a research topic. Over the lifetime, 635 publications have been published within this topic receiving 239107 citations.

A Dynamic Interaction of Coomassie Dye with the Glycine Transporters N-termini.

Abstract: Coomassie Brilliant Blue interacts with proteins and even though the interactions exhibit variation due to the amino acid content, reported dye interactions with individual proteins appear to be relatively stable. Here we report an atypical dynamic interaction of glycine transporters 1 and 2 N-termini with Coomassie dye, resulting in intramolecular interference with their Bradford assay. These proteins exhibit classic protein-Coomassie G-250 complex with absorption maximum at 595 nm, which within minutes starts to decrease and parallel increase of absorbance shoulders above 300 and 700 nm is observed. Interestingly, these effects are eliminated upon fusion of glycine transporters N-termini with glutathione S-transferase protein or by the presence of glutathione S-transferase or bovine serum albumin in the same solution. Circular dichroism data revealed largely unstructured character of glycine transporters N-termini, which suggests that dynamic properties of these protein- Coomassie complexes might be a signature of high flexibility and protein disorder. The assay might potentially reveal similar domains in other proteins and help to associate them with particular functions.

A new method of spectrophotometric determination of poly(diallyldimethylammonium chloride) concentration

Abstract: Summary – Spectrophotometric method of protein determination, widely known as the Bradford method, has been applied for quantitative determination of poly(diallyldimethylammonium chloride) (PDDA) monomer units in aqueous solution. In phosphoric acid environment the PDDA polymer stabilizes blue form of the Commasie Briliant Blue G-250 dye having a broad absorption band. Increase in absorbance at wavelengths in the range from 570 to 630 nm follows the increase in monomer units of polymer concentration up to 0.042 mmole/dm 3 . Calibration curves fulfilling second-degree polynomial equations can be determined for PDDA monomer units concentrations not exceeding 0.03 mmole/dm 3 .

COMPARISON STUDY OF THERAPEUTIC PROPERTIES OF PROTEINS AND SECONDARY METABOLITES FROM CARICA PAPAYA Original Article

Abstract: Objective: The current study aims to compare the therapeutic potential of protein extracts and secondary metabolites extracts using methanol, ethyl acetate and hexane from both the fruits and seeds of Carica papaya. Methods: All of the crude proteins and secondary metabolite fractions extracted from the fruits and seeds of Carica papaya were assessed and compared in DPPH free-radical scavenging assay for antioxidant activities and brine shrimp lethality assay for cytotoxic potentials. Protein content was quantified by Bradford assay while total phenolic and flavonoids contents were determined by Folin-Ciocalteu and aluminum chloride colorimetric methods accordingly. Bioactive protein molecules and secondary metabolite fractions were then characterized and analyzed in SDS- PAGE and silica thin layer chromatography respectively. Results: Evidence demonstrated that the secondary metabolite extracts of ethyl acetate fraction of the seeds of Carica papaya have the highest antioxidant activity (IC 50 value of 25.97 µg/ml) as well as cytotoxicity activity (LC 50 value of 142.27 µg/ml) in comparison to other crude proteins, methanol or hexane extracts. Notably, crude protein from fruits possesses relatively high antioxidant (IC 50 value of 34.62 µg/ml) and cytotoxicity (LC 50 Conclusion: This study proved that the crude protein from fruits and ethyl acetate fraction from seeds and fruits of Carica papaya have great potential to be further developed into therapeutic drugs in future. value of 222.52 µg/ml) activities. The presence of bioactive phenolic and flavonoid in crude secondary metabolite extracts and bioactive protein molecules in crude protein extracts confer the high antioxidant capacity and cytotoxic potential of Carica papaya.

Measurement of protein in lipid extracts.

Abstract: Publisher Summary This chapter discusses the measurement of protein in lipid extracts In the course of studies of organic-solvent-soluble proteins, a variety of classic protein assay methods have been found to be inapplicable or involving excessive effort to reduce interference as a result of the presence of lipids in the mixture The simplest resource, extracting the lipids away from the protein by the use of organic solvents, fails because of the solubility of the protein in organic solvents The chapter explores that 2,4,6-trinitrobenzene sulfonic acid (TNBS) of a suitable quality is obtained commercially as a pale yellow crystalline material It may be recrystallized from 1 M HCl or from 2-butanone-petroleum ether mixtures As the crystalline material may have a variable degree of hydration, the stock solution of 003 M TNBS in butanol (tertiary : secondary, 9:1 v/v) is conveniently diluted from a stronger solution after an alkalimetric check on its concentration Organic solvents and potassium tetraborate are the analytical reagent grade or equivalent The 6 M HCl used is the easily prepared 61 M azeotrope; a dilution of 12 M HCl would be equally satisfactory