Preparation of enzymically active lysozyme from sputum and its distribution between the sol and gel phases

An improved method for the isolation and purification of lysozyme from sputum from bronchitic patients is presented. Enzymically active lysozyme in pure form was obtained in practically quantitative yields. The method was used to quantify the lysozyme content and to determine its distribution between the sol and gel phases of the secretion, which were separated by centrifugation. It was shown that lysozyme is concentrated in the mucin-containing gel phase, from which it can be liberated with high concentrations of salt. Evidence supporting an electrostatic binding mechanism between mucin and lysozyme is presented.