text: Enzymatic reactions are limited by the need for aqueous solvent and near-neutral reaction conditions. PLE hydrolyses are typically carried out with a phosphate buffer to maintain the pH between 7 and 8. As solubility of the substrate in the aqueous medium is critical, a small amount of a polar organic co-solvent is sometimes added to the aqueous solution of the enzyme. Commercially available PLE is of sufficient purity for most applications.