THE PH-DEPENDENCE OF THE STRUCTURAL STABILITY OF PATATIN

This paper presents the structural stability of patatin, the major pot ato (Solanum tuberosum cv. Bintje) tuber protein. Using far- and near- ultraviolet circular dichroism and fluorescence spectroscopy, the conf ormation of patatin was studied under various conditions as a function of temperature. Patatin is a protein that unfolds partly due to eithe r heat or acid treatments. When the protein is highly structured at th e start of a heat treatment (near-neutral pH), an apparent two-state t hermal unfolding is absented. At low pH, when the starting conformatio n is already irreversibly unfolded to a certain extent, only minor cha nges occur upon heating. The residual structures could be part of one or more relatively stable domains. The acidic and the thermal unfoldin g appear to be similar, but are not identical. These results could con tribute to an improved method of isolation, enabling novel food applic ations of potato proteins.