Protein Detection, Quantitation and Analysis

eBook: Nucleic acid & protein quantitation

Streamline absorbance assays for nucleic acid & protein quantitation

Absorbance microplate readers are widely used in basic research, drug discovery, bioassay validation, quality control, and manufacturing processes in pharmaceutical, biotech, food and beverage, and academic industries. These readers provide rapid and sensitive measurements of a variety of analytes across a wide range of concentrations for a wide range of assays, including ELISAs, microbial growth, detection of key compounds and contaminants, and protein quantitation.

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ELISA

Enzyme-linked immunosorbent assays (ELISAs) are used to measure the amount of a specific protein, using a microplate format, and results are most often detected via absorbance in the visible wavelength range. Chemiluminescent and fluorescent ELISA formats offer enhanced sensitivity for accurate quantitation of less abundant analytes.

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Fluorescent protein applications

Proteins inside eukaryotic cells exist in a dynamic state, in a highly-regulated balance between synthesis and degradation. Whereas protein synthesis is well-understood after decades of study, major advances in our knowledge of protein degradation have occurred only in the last two decades. Fluorescent proteins can be used as reporters to investigate protein degradation and related cellular signaling pathways.

Learn more about how fluorescent proteasome sensors have been used in our application notes.

• Multiplexing Fluorescent and Chemiluminescent Live Cell Reporters to Dissect NFkB Signal Transduction Requirements
• Measurement of Proteosome Inhibition in Live Cells on the Analyst® GT, FLEXstation® and Gemini EM Microplate Readers Using the BD Biosciences Proteasome Sensor

IgG Quantification

In therapeutic protein engineering and cell line development, IgG quantification is the process of measuring the amount of immunoglobulin G (IgG), a common class of therapeutic proteins, produced by a genetically modified cell line. This is important for evaluating and monitoring the productivity of the cell line and selecting the best candidate for further development of therapeutic antibodies.

• High-throughput IgG quantitation platform for clone screening during drug discovery and development

• Poster: High-throughput IgG quantitation platform for clone screening during drug discovery and development

• Qualitative measurement of SARS-CoV-2 spike and nucleocapsid IgG antibodies in serum samples

• Virology and Vaccine Research: Microplate Reader Solutions

Measure protein concentration (Bradford, BCA, etc)

Protein concentration can be measured directly via absorbance at 280 nm in a UV spectrophotometer, or indirectly using colorimetric methods such as BCA or Bradford assays. Protein can even be quantitated using fluorometric methods.

Here are some application notes on protein quantitation you may find of interest:

• Streamline BCA-based protein quantitation on the SpectraMax iD5 reader
• Measure total protein in cell lysates with SpectraMax ABS Plus Microplate Reader
• Protein quantitation with the EMax Plus Microplate Reader
• Direct protein quantitation using the SpectraDrop Micro-Volume Microplate
• Using the NanoOrange Protein Kit with SpectraMax Microplate Readers

Tryptophan detection

The intrinsic fluorescence of proteins is due to the aromatic amino acids tryptophan, tyrosine, and phenylalanine. Tryptophan dominates the emission of proteins and is the most sensitive to solvent polarity and the local environment. Analysis of changes in tryptophan fluorescence can yield information on protein denaturation and conformation.

In these application notes, we demonstrate performance of the SpectraMax® multi-mode microplate readers for assays measuring intrinsic tryptophan fluorescence.

• Measure intrinsic tryptophan fluorescence on the SpectraMax iD3 microplate reader
• Intrinsic tryptophan detection with the SpectraMax i3 Multi-Mode Microplate Platform

Western blotting

Western blotting is a popular technique used for protein detection and quantitation. Learn about the various techniques used to detect proteins on western blot membranes including colorimetric, fluorescence, and chemiluminescence. We’ll also introduce you to a novel, first-of-its-kind western blot detection system on a multi-mode microplate reader.

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