Based on Global Two-Dimensional Structural Properties

Methods Based on Global Two-Dimensional Structural Properties 

Simple alternatives to hydrophobic atomic or polyatomic fragmental constants that have been explored include semiempirical polarity parameters and structural parameters calculated from the two-dimensional molecular struaure. 

The polarity parameter A is a different approach based on Eq. [5] using another structural parameter of amino acid side chains. For the side chain of each amino acid in the free zwitterionic form and in protected form ° (amide plus ester), Eq. [5] permitted calculation of the polarity parameter A from the computed molecular volume V and the experimental distribution coefficient log D. 

These parameters (Table 7) reflect how the global polarity of the side chain is affected by the polarity of the backbone, a phenomenon of major importance in molecular biology. Such intramolecular effects encoded in the A 

Calculation of Lipophilicity Using Charge Densities (Kloptnan and Iroff) 

---