The Aliphatic Index is defined as the relative volume occupied by the aliphatic side chains, Aliphatic Index = X(Ala) + aX(Val) + b(X(Ile) + X(Leu)), where X(Ala), X(Val), X(Ile), X(Leu) are mole percent of alanine, valine, isoleucine and leucine. The constants a and b are the relative volume of aliphatic side chains to that of alanine side chain where, a ≈ 2.9 and b ≈ 3.9. The Boman Index is equal to the sum of the solubility values for all residues in a sequence. It gives an estimate of the peptides' likelihood to bind to membranes or other receptors. Peptides with Boman Index > 2.48 are said to exhibit high binding potential. Isoelectric point Compiled by A. D. is the pH at which the net charge of a protein becomes zero. The charges at various pH levels Compiled by A. D. are determined according to the known isoelectric points of the amino acids.