ENZYME ENVELOPES ON COLLOIDAL PARTICLES

A new method has been developed for the preparation of insoluble proteins. The method involves the adsorption of protein as a monolayer onto colloidal silica particles, followed by intermolecular crosslinking with glutaraldehyde. Insoluble bovine trypsin prepared by this method was obtained in about 99% yield with 80% retention of esterase activity. This activity was only partially inhibited by protein inhibitors of trypsin (M.W. 9,000-28,000). Proteolytic activity was approximately 17% that of native trypsin. These particles are easily sedimented, but are nonetheless readily dispersible to form sols. The method appears to be of general applicability for the preparation of insoluble proteins as stable envelopes on colloidal particles. © 1969.