Cupin-1.1 Adsorption\nLayers at the Surface of 8 M\nUrea Solutions

The adsorption layers of cupin-1.1, one of the two evolutionary\nconserved β-barrel domains of vicilinthe garden pea\nstorage globulinat the liquid–gas interface were studied\nby a few methods of the surface chemistry. The kinetic dependencies\nof the surface pressure of cupin-1.1 solutions in 8 M urea overlap\nin a single master curve if the surface pressure is plotted as a function\nof the normalized time. The analysis of the master curve allows separation\nof a few adsorption steps including the induction period, the regions\nof the diffusion-controlled and barrier-controlled adsorption kinetics,\nand a plateau region of slow adsorption. Another master curve can\nbe constructed from the dependencies of the dynamic surface elasticity\non surface pressure. This curve has some similarities with the corresponding\nresults for recently studied cupin-1.1 spread layers on the surface\nof urea solutions and gliadin adsorption layers. There are also important\ndistinctions with the master curve for adsorption layers of cupin-1.1\nin the system without denaturants. This difference can be connected\nwith the formation of larger and more rigid aggregates in pure water\nthan the aggregates in urea solutions.