What are two ways to measure the total amount of all proteins in a purification sample? 1) Calculating the yield and 2) calculating the purity of a purification. 1) Measuring absorbance at 280nm and 2) using an enzymatic assay for your protein of interest. 1) Quantitating the amount of your protein of interest using binding of a labeled antibody (e.g. an ELISA) and 2) using a dye-binding assay. 1) Measuring absorbance at 280nm and 2) using a dye-binding assay