Musculoskeletal ProteinAnalysis Techniques - A Review

There have been a large number of experimental methods for purifying and analyzing proteins from the sample of interest. Determination of protein concentration is often the key step and is common to many applications in protein research and life sciences. The most commonly used quantitative techniques to measure the protein concentration are Amino acid analysis, Biuret assay, Bradford assays, Folin- Lowry assay, Bicinchoninic (BCA) assays, UV absorbance assays and Antibody-based assays such as ELISA and Western Blotting. Some of the qualitative methods that are used to detect different types of proteins and amino acids are Ninhydrin test, Xanthoproteic test, Millon’s test, Sulfur test, Hopkins-Cole test, and Nitroprusside test. Chromatographic analysis can also be carried out on an either qualitative or quantitative basis to purify complex protein mixtures based on their properties such as size, solubility, charge, hydrophobicity and bio-specific interaction. Selection of these assays is based upon the ease of performance, range of concentrations, sensitivity, and interfering substances contained in the complex mixture. The purpose of this review is to provide an assessment of commonly used chromatographic and colorimetric methods for the determination of protein concentration