A cell lysis buffer is a vital first component in any isolation protocol. It enables molecules of interest to escape by breaking down the cell membranes and compartments that enclose them. It does this in a way that disrupts membrane chemistry while still preserving the integrity of target molecules.
NaCl plays a key role in lysis buffer. It keeps proteins soluble and increases the ionic strength of the buffer, which facilitates the disruption of molecular interactions. A low concentration of NaCl helps screen ionic interactions and prevents nonspecific binding of proteins to the column while allowing the target protein to bind the column.