Protein Quantitation (Bradford, Lowry, BCA, DC)
Protein concentration can be measured directly, via absorbance at 280 nm in a UV spectrophotometer, or indirectly, using colorimetric methods such as BCA or Bradford assays. Absorbance quantitation is easy to do as it does not require additional reagents, but colorimetric methods offer greater sensitivity and are often preferred when samples are precious. Both can be performed in a UV-vis spectrophotometer or in an absorbance microplate reader.