For cells grown in tissue culture, the most useful method of lysis is treating with detergents, as described in this protocol. Non-ionic detergents, such as NP-40, solubilize the plasma and intracellular membranes, break many weak intermolecular bonds, and solubilize most of the commonly studied protein antigens. RIPA lysis buffer may be used as a more rigorous extraction buffer to release all but the insoluble proteins of the cell and to break most weak noncovalent interactions. - [Read Lysing Tissue-Culture Cells for Immunoprecipitation Protocol]
UV Absorbance 280 nm Protein Determination. Simple and quick method to accurately quantitate total protein in purified material or approximately quantitate total protein in crude lysates or partial purified material. Quantitation of the amount of protein in a solution is possible in a simple spectrometer. Absorption of radiation in the near UV by proteins depends on the Tyr and Trp content (and to a very small extent on the amount of Phe and disulfide bonds). Dr. Mario Lebendiker - [Read UV Absorbance 280 nm Protein Determination]