Review of methods for determination of total protein and peptide concentration in biological samples

Abstract

Clinical proteomics can be defined as the use of proteomic technologies to identify and measure biomarkers in fluids and tissues. The current work is intended to review various methods used for the determination of the total concentration of protein or peptide in fluids and tissues and the application of such methods to clinical proteomics. Specifically, this article considers the approaches to the measurement of total protein concentration, not the measurement of the concentration of a specific protein or group of proteins in a larger mixture of proteins. The necessity of understanding various concepts such as fit-for-use, quality-by-design, and other regulatory elements is discussed, as is the significance of using suitable standards for the protein quality of various samples.

Monitoring of polypeptide content in the solid‐state fermentation process of rapeseed meal using NIRS and chemometrics

“…Currently, methods such as liquid chromatography‐UV (LC‐UV) (Chen, Garrido Arias, Adams, & Van Schepdael, ), biuret technique (Hortin & Meilinger, ), modified bicinchoninic acid assay (Kapoor et al, ), and UV–VIS spectrophotometry has been used to determine the peptide concentration in biological samples (Sapan & Lundbald, ), and so forth. These methods, however, are considered traditional.…”

Colorimetric determination of total protein content in serum based on the polydopamine/protein adsorption competition on microplates

“…the most abundant protein in serum, 49 indicates that should be possible to estimate the total protein content even for complex matrix containing a large variety of macromolecules and electrolytes, therefore the colorimetric assay here developed appears potentially complementary to current methods in clinical proteomics and food 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 analysis. [30][31][32][33][34] Notably, the linear dynamic range here found for polydopamine-protein adsorption competition (0.015 ÷ 1.00 g L !1 ) is comparable to that of other methods for quantitative estimate of protein content, 32 like the direct spectrophotometric assays based on the extinction coefficient of the protein, or the colorimetric assays based on copper reduction by peptide bonds and subsequent complex formation with bicinchoninic acid (BCA), or oxidative reaction with the Folin-Ciocalteau reagent (Lowry assay). However, our model seems to show some advantages for protein determination derived from the low-cost and safe sample analysis and its matrix-independent outcomes.…”

“…28 Subsequently, we have exploited for the first time the optical properties of PDA to follow the polymer growth in presence of proteins (as templates), mimicking the molecular imprinting procedure. We show the dependence of MIP formation upon protein concentration that allows to describe a competition between PDA and macromolecules for surface binding, useful for rational development of imprinted biosensors, 7 to enhance the tissue integration of polymeric implants, 29 and introduces a facile, low-cost and safe analytical method for estimation of total protein content even in complex matrix like human serum, by providing a suitable alternative to current diagnostic tools in medicine, [30][31][32][33] as well as in food analysis. 34…”

Pharmacological, toxicological and neuronal localization assessment of galantamine/chitosan complex nanoparticles in rats: future potential contribution in Alzheimer’s disease management

“…Aliquots of brain homogenate supernatants were assayed for total protein using Biuret method, which was selected as it is sensitive yet involves a single incubation period (Sapan & Lundblad, 2015). Brain supernatants (25 ml) or standard serum albumin (25 ml) were mixed with 1 ml of Biuret reagent and incubated for 10 min at 37 C. The absorbance (A) was determined at 550 nm using a UV-Visible spectrophotometer.…”