ADSORPTION OF RIBONUCLEASE AT AIR-WATER INTERFACE AND ON PHOSPHOLIPID MONOLAYERS

Adsorption of ribonuclease at the air-water interface and on lecithin and cephalin monolayers was followed using a tritiated acetic anhydride-labeled protein. At the air-water interface, the ribonuclease was adsorbed in two distinctly different and not necessarily monomolecular layers. The first layer several molecules thick seemed to be completely or partly composed of unfolded protein molecules. The second layer seemed to be composed of native ribonuclease molecules in a bidimensional crystalline arrangement. On a condensed phospholipid monolayer, only a one-layer adsorption of native ribonuclease molecules was obtained. When the phospholipid monolayer was expanded, the adsorption characteristics of the ribonuclease on it became similar to those at the air-water interface. © 1969.