Lab 10 - Protein Quantitation (Bradford Protein Assay)

From the Quick Start™ Bradford Protein Assay

instruction manual (BioRad)

Today we did a protein quantitation using BioRad's Quick Start™ Bradford Protein Assay, a method in which a dye reagent is used (Coomassie Brilliant Blue) to bind to proteins and measure its absorbance. The more concentrated the protein it binds, the darker the blue resultant color, and the greater the absorbance at 595 nm.

Two standard proteins are used, bovine serum albumin (BSA) and gamma-globulin, to generate absorbance vs. protein concentration curves and then interpolate the absorbance of problem samples to estimate their concentration. The protein samples obtained from the Hydrophobic Interaction Chromatography (HIC) are used as problem samples.

This method is applied when researchers in proteomics discover a new protein and are trying to gather information about it. In our case, we "discovered" GFP, although we wouldn't have a name yet, had it been a truly newly discovered protein.

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Lectures, chapters 9 & 10 - Transcriptional gene regulation in prokaryotes and in eukaryotes

Yesterday we covered most of the relevant section in chapter 9, on transcriptional gene regulation in prokaryotes. Today we finished and started chapter 10, on transcriptional gene regulation in eukaryotes.

Transcriptional gene regulation in prokaryotes covers the basics of gene regulation, including the concepts of global and specific regulation, activators and repressors, and regulation at transcription termination.

Transcription gene regulation in eukaryotes adds layers of complexity, like the role played by specific transcription factors, accessibility to DNA condensed in nucleosomes, and the role played by a mediator complex during gene activation.

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