Microvolume Protein Analysis
Microvolume Protein Analysis - Related Videos
10:29
Microvolume Protein Concentration Determination using the NanoDrop 2000c Spectrophotometer
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Cited by 129 •
2009
Microvolume samples are quantified by a spectrophotometer system that uses natural surface tension to retain samples without the use of cuvettes or capillaries. The dynamic range of protein concentrations and speed by which they can be measured are greatly increased with this method.
09:28
NanoDrop Microvolume Quantitation of Nucleic Acids
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Cited by 426 •
2010
The use of NanoDrop microvolume systems as practical and efficient alternatives to traditional nucleic acid quantitation methodology is described through the demonstration of two microvolume nucleic acid quantitation protocols.
08:46
Green Fluorescent Protein-based Expression Screening of Membrane Proteins in Escherichia coli
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Cited by 34 •
2015
A streamlined approach to screening for the expression of recombinant membrane proteins in Escherichia coli based on fusion to green fluorescent protein is presented.
05:43
A Protein Preparation Method for the High-throughput Identification of Proteins Interacting with a Nuclear Cofactor Using LC-MS/MS Analysis
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Cited by 1 •
2017
We have established a method for the purification of coregulatory interaction proteins using the LC-MS/MS system.
08:59
Analysis of Protein Folding, Transport, and Degradation in Living Cells by Radioactive Pulse Chase
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Cited by 8 •
2019
Here we describe a protocol for a general pulse-chase method that allows the kinetic analysis of folding, transport, and degradation of proteins to be followed in live cells.
FAQs
Ultraviolet-based measurements rely on protein absorbance by aromatic amino acids, particularly at 280 nm. The instrument converts the detected absorbance into a concentration using either calibration information or an established extinction coefficient, which links absorbance to the amount of protein present. This mechanism makes the reading sensitive to the protein’s composition, not simply to sample volume.
Fluorescence and reagent-based assays provide alternatives when ultraviolet absorbance is not the selected readout. In these workflows, proteins either generate a fluorescence signal or produce a color change after reacting with assay reagents. The measured signal is then related to protein concentration through comparison with standards, allowing microvolume analysis to use different detection principles within the same broader task.
They provide the reference needed to translate an optical signal into a concentration. A calibration approach compares the sample response with responses from standards, whereas an extinction coefficient supplies an established relationship for the protein measurement. Without one of these reference frameworks, absorbance, fluorescence, or color intensity would not directly provide a quantitative protein value.
Beyond concentration, some workflows use microvolume protein analysis to assess purity or composition. This extends the measurement from asking how much protein is present to evaluating what the sample contains or how suitable it may be for later work. Such information can help determine whether a preparation is ready for normalization, electrophoresis, or mass spectrometry.
A basic workflow starts by providing a few microliters of the biological sample to an instrument or assay format, selecting the relevant detection principle, and obtaining an optical signal. The result is interpreted against calibration standards or an extinction coefficient. Researchers can then record concentration, and where supported by the workflow, purity or composition, before using the sample downstream.
In biology, this analysis is useful when sample availability is limited or when rapid measurements support an experiment efficiently. Cell biology, biochemistry, proteomics, and molecular biology workflows can use the result to assess protein yield, normalize inputs between samples, monitor purification, or evaluate material before electrophoresis and mass spectrometry.