Structural and immunological studies on the protoplast membrane of the yeast Candida utilis.

Cell membranes of the yeast Candida utilis isolated by lysis of protoplasts have been shown to be lipoprotein in nature. Electron microscopy shows that Mg(++) is responsible for maintaining the integrity of the membrane. A close serological relationship was found between membranes and cell walls isolated from the yeast. This relationship was exhibited not only by membranes obtained by strepzyme treatment but also by those obtained from the action of helicase enzyme. No such relationship existed between membranes and whole cells. Related data have been obtained by treatment of yeasts with different digestive enzymes. All of the results suggest that the protoplast membrane possesses traces of structural cell wall material. This material is detectable by serological tests, but not by electron microscopy.