Spectrum for the Applicability of the Fuzzy-Oil-Drop Model

Objective: The structure of proteins has encoded the record of biological activity in the form of a specific polarity-hydrophobicity relationship system. Structural changes related to the function change this record according to the process stages in which the given protein is used. Methods: The fuzzy oil drop model (FOD-M) was used to describe such phenomena in the aspect of the polarity/hydrophobicity relationship. Results: Application of this model allows quantitative assessment of the status reflecting the specific nature of individual proteins. Examples of this application are discussed in this publication The local exposure of hydrophobicity is a specific record of the possible hydrophobic interaction with another protein, providing an agent stabilising such a system. Conclusions: The local hydrophobicity deficit means the presence of a cavity, ready to interact with a substrate in the case of an enzyme. Other cavity types may be adapted to interact with a ligand comprising a permanent ingredient of a complex, often guaranteeing biological activity. In the case of membrane-anchored proteins, exposure of hydrophobic residues is a typical example, rendering the proteins stable in the membrane environment.