Protein Concentration Assay
Protein Concentration Assay - Related Videos
19:16
The Importance of Correct Protein Concentration for Kinetics and Affinity Determination in Structure-function Analysis
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Cited by 27 •
2010
We apply label-free protein interaction analysis using Biacore X100 for structure-function analysis of the binding of several cystatin B mutants to papain through kinetic characterization. Calibration-free concentration analysis (CFCA) measures the concentration of protein with retained binding activity without the need for a standard curve. We show that confirmation of concentrations using CFCA increases the reliability of the kinetic analysis and that kinetic constants can reliably be...
06:35
Linearization of the Bradford Protein Assay
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Cited by 290 •
2010
The accuracy and sensitivity of protein determination by the rapid and convenient Bradford assay is compromised by intrinsic nonlinearity. We show a simple linearization procedure that greatly increases the accuracy, improves the sensitivity of the assay about 10-fold, and significantly reduces interference by detergents.
02:49
Bacterial Culture Filtrate Protein Concentration using an Ultrafiltration Device
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2025
This video demonstrates the isolation and concentration of bacterial culture filtrate proteins, which include bacterial extracellular vesicles, using ultrafiltration. The concentrated extracellular vesicles serve as diagnostic markers for disease detection.
02:52
Calcification Assay to Measure Calcium Concentration in Aortic Valve Interstitial Cells
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2025
This video demonstrates an assay technique for assessing the calcification of the aortic valve interstitial cells in vitro. The assay helps to quantify the calcium concentration using the arsenazo III reagent, a calcium-sensitive dye that reacts with calcium ions to form a purple-colored calcium-arsenazo complex.
04:42
Assays for Qualitative and Quantitative Assessment of Mouse Urine Glucose Concentrations
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2026
Source:Tumininu S. Faniyan1, Dennis J. Samuel1, Kavaljit Chhabra11University of Rochester Medical Center.This video demonstrates a procedure for collecting mouse urine and assessing its glucose levels. To evaluate the glucose level, immerse a test strip coated with enzymes and a chromogenic dye into the sample, initiating a color change that indicates the glucose levels. For quantifying urine glucose levels, introduce a urine sample to a multiwell plate with escalating glucose concentrations,...
FAQs
In a colorimetric assay, proteins react with chemical reagents to produce a colored signal. The color intensity increases as protein concentration rises, allowing the sample signal to be compared with standards containing known concentrations. This relationship provides a concentration estimate while making reagent behavior and compatibility important considerations for reliable measurement.
Known standards provide the reference needed to relate an observed signal to protein concentration. By comparing a sample’s absorbance or color intensity with the standards, researchers can estimate how much protein the sample contains. Without this comparison, the measurement would indicate signal strength but would not establish the sample’s concentration.
Direct ultraviolet measurements assess proteins through their ability to absorb ultraviolet light, whereas colorimetric methods measure a reagent-generated color. These approaches differ in sensitivity and in which reagents or sample conditions they tolerate. Selecting between them therefore depends on the required measurement performance and compatibility with the biological sample or downstream analysis.
Assay selection should account for the method’s sensitivity and its compatibility with the reagents present in the sample. A suitable approach produces a measurable signal under the sample’s conditions without interfering with planned analyses. This choice matters because an incompatible or insufficiently sensitive assay can reduce the accuracy of later comparisons and sample preparation.
A typical workflow measures the sample signal using either ultraviolet absorption or a reagent-based color response, then compares that signal with results from standards of known concentration. The resulting estimate can be used to adjust or normalize sample amounts before electrophoresis, enzyme studies, immunoassays, or protein purification.
Determining concentration allows researchers to compare experiments using appropriately normalized protein amounts. More consistent input supports interpretation of electrophoresis results and helps prepare samples for enzyme studies, immunoassays, and purification workflows. In each case, the assay links the amount of biological material used with the outcome being analyzed.