On the Absence of Ubiquitous Structural Protein Subunits in Biological Membranes*

Although biological membranes exhibit a great diversity of functions, a of general features appear to be similar in all membranes. In order obtain a general concept of membrane structure and function, attempts have made to find protein subunits responsible for the general structure of , and numerous reports on such “structural proteins” appeared the past decade. It was assumed that the structural proteins necessary to maintain the membrane structure, whereas the special functions each membrane were maintained by other proteins, e.g., enzymes.