Submaxillary gland of mouse: properties of a purified protein affecting muscle tissue in vitro.

A protein from the salivary gland of mice has been highly purified. It affects embryonic muscle tissue in vitro and has both esterase and peptidase activities. Addition of the pure protein to tissue culture in synthetic medium causes dissociation of muscle fibers in individual myoblasts with loss of myosin. This biological activity, as well as the esterase activity, is inhibited by low concentrations of phenylmethanesulfonyl fluoride; this suggests that the effect on the tissue is a consequence of the protein's enzymatic activities.