Protein Quantification

Protein quantification kits for accurate, sample-matched BCA, Bradford, and Biuret assays

The right protein quantification assay gives you accurate total protein measurements that remain compatible with your sample matrix, whether you are loading a gel, normalising an ELISA plate, or preparing a proteomics sample. Three colorimetric formats cover most laboratory needs: BCA assays suit cell lysates prepared with RIPA or NP-40 buffers and tolerate moderate detergent concentrations, Bradford assays deliver results in five minutes but are more susceptible to detergent and basic buffer interference, and Biuret assays are simple and reagent-stable but less sensitive, suiting samples with higher protein concentrations. BCA, Bradford, and Biuret formats are all validated for lysate and purified protein inputs. For GFP-tagged protein quantification independent of total protein, an anti-GFP antibody sandwich assay gives you selective GFP detection in crude cell lysates without gel separation.

Three dimensions: assay chemistry (BCA tolerant of detergents and broadly accurate; Bradford fast and detergent-sensitive; fluorescence-based dyes give highest sensitivity and lowest sample consumption; Lowry deprecated for routine use), sample compatibility (lysate, biofluid, purified protein each have suitable methods), and dynamic range (BCA ~10 microgram per mL; Qubit-style fluorescence to ~10 nanogram per mL). Elabscience covers standard total-protein assays; Bertin Technologies offers fluorescence-based formats. For Western normalisation or proteomics sample-loading BCA is the safest default; fluorescence-based dyes are the choice for low-input or scarce samples.