On characterization of physical properties of amino acids

For correlating selected properties of amino acids we use the variable conn ectivity index (1)chi (f) which is obtained by generalizing the connectivit y index (1)chi by introducing variable weights. The generalized connectivit y index assigns to each atom a parameter yet to be determined during the re gression analysis so that the standard error of estimation becomes as small as possible. Using the weights -0.65, 5.25, 0.20, and 0.50 for carbon, oxy gen, nitrogen, and sulfur, respectively, we obtained a multivariate regress ion with the regression coefficient 0.9865, standard error of 4.73, and Fis her ratio F = 506 for partial molar volumes of amino acids. (C) 2000 John W iley & Sons, Inc.