What is protein quantification?
Protein quantification or total protein content by colorimetric methods such as absorbance at 280, Bradford or BCA assays and quantitative amino acid analysis. Protein quantification is necessary to understand the total protein content in a sample or in a formulated product.
What is a fluorescent protein assay?
Choose the right fluorescent protein assay for your sample
| Qubit Protein BR Assay | |
|---|---|
| Best for | Rapid quantitation of small number of samples |
| Assay range (sample volume) | 100 µg/ml to 20 mg/ml (10–20 µL) |
| Assay incubation time and temperature | 10 min at RT |
| Detection wavelength (nm) | 470/570 |
What is BCA assay used for?
The BCA protein assay is used for quantitation of total protein in a sample. The principle of this method is that proteins can reduce Cu+2 to Cu+1 in an alkaline solution (the biuret reaction) and result in a purple color formation by bicinchoninic acid.
What are the different methods of protein quantitation?
Protein quantification techniques can include bicinchoninic acid assay (BCA), variations of high-performance liquid-based chromatography (HPLC) and the use of fluorescently labelled or radio-chemically labelled proteins.
Why is determining protein concentration important?
Why do we need to measure protein concentrations? Proteins are important to study because they form the basis of cellular function in plants and animals. Furthermore, protein concentration analysis is needed to determine the quantity and quality of protein and state of biological reactions.
Which protein assay is the best?
Top 5 Protein Quantification Assays
- Bicinchoninic Acid (BCA) This colorimetric, two-step assay was originally developed in 1985 – making it a baby compared with the 64-year-old Lowry assay!
- Bradford.
- Folin-Lowry.
- Kjeldahl.
- Ultraviolet Absorption.
What is NanoOrange?
The NanoOrange Protein Quantitation Kit contains a very sensitive and easy assay for protein quantitation, with detection as low as 10 ng/mL of protein in solution. This fluorescent dye is suitable for use with spectrofluorometers and microplate readers.
What is the principle of BCA protein assay?
The principle of the bicinchoninic acid (BCA) protein assay1 relies on the formation of a Cu2+-protein complex under alkaline conditions, followed by reduction of the Cu2+ to Cu1+. The amount of reduction is proportional to the amount of protein present.
What does a BCA standard curve show?
A protein assay, such the BCA Protein Assay, is an excellent tool for estimating the protein concentration of a sample. The intensity of the colored reaction product is a direct function of protein amount that can be determined by comparing its absorbance value to a standard curve.
How does Bradford assay work?
The Bradford protein assay is a time-tested colorimetric assay. When the Bradford reagent (acidified Coomassie Brilliant Blue G-250) binds to proteins, the dye undergoes a color change in the visible spectrum, with the absorbance maximum moving from 470 to 595 nm.
How do we measure protein concentration?
The quickest way to estimate the amount of protein in solution is to use UV-vis to measure absorbance directly, but this is generally not very accurate or sensitive. Highly accurate quantitation of most proteins can be achieved using either a Bradford or bicinchoninic acid (BCA) assay.
What is the EZQ™ protein quantitation kit?
The EZQ™ Protein Quantitation Kit provides a fluorescence-based protein assay that facilitates fast quantitation of protein samples prepared for gel electrophoresis.
What is the excitation/emission maxima of Quant-iT protein reagent?
The fluorescence signal exhibits excitation/emission maxima of 470/570 nm and is stable for three hours at room temperature. The Quant-iT protein reagent is an improved formulation of Molecular Probes NanoOrange reagent, which is described below.
How does the Quant-iT protein assay kit (q33210) work?
The Quant-iT Protein Assay Kit ( Q33210) simplifies protein quantitation without sacrificing sensitivity. This protein assay exhibits a detection range between 0.25 and 5 µg protein, and the response curve is sigmoidal (quasi-linear from 0.5 to 4 µg) with little protein-to-protein difference in signal intensity ( Figure 9.2.2 ).
Why is protein quantitation important in biochemistry?
The measurement of protein concentration in an aqueous sample is an important assay in biochemistry research and development labs for applications ranging from enzymatic studies to providing data for biopharmaceutical lot release. Spectrophotometric protein quantitation assays are methods that use U …