Preparation of Cell Extracts for Purification of Soluble Proteins Expressed in E. coli

Recovery of intracellular proteins requires disruption of the host cell before the target protein is extracted and isolated. For cells enveloped in cell walls (such as Escherichia coli ), vigorous methods are often required. This protocol focuses on E. coli lysis by sonication. Also included are methods for lysis by freeze–thaw and enzymatic treatments.