What is the first method to develop the hydropathy scale?

The first method to develop the hydropathy scale involves analyzing the polarity of amino acids using partition coefficients. This approach focuses on the solubility of amino acids in nonpolar versus polar solvents, which allows for the assessment of their hydrophobic or hydrophilic properties. Partition coefficients provide a quantitative measure that helps rank amino acids according to their tendency to remain in aqueous (polar) environments versus organic (nonpolar) solvents.

This method is foundational in biochemistry because it directly relates to the behavior of proteins in biological systems, influencing folding, function, and interaction with other biomolecules. By determining how different amino acids partition between two phases, researchers could categorize them from hydrophobic to hydrophilic, leading to the establishment of the hydropathy scale that is widely used to predict the transmembrane domains of proteins and their interactions within membranes.