Abstract: A new set of descriptors, VHSEH(principal component score vector of hydrophobic, steric, electronic properties, and hydrogen bonds contributions), was derived from principal components analyses of 171 physicochemical variables of 20 natural amino acids separately according to different properties described, namely, hydrophobic, steric, and electronic properties, hydrogen bonds contributions. VHSEH scales were employed to express the structures of oxytocin analogues, antimicrobial peptides and angiotensin-converting enzyme inhibitors. The correlation coefficients R₂ and cross validation Q₂ for the multiple-variable models by PLS and PLS by D-Optimal Designs of oxytocin analogues were 0.958 and 0.903, 0.957 and 0.845, respectively. R₂ and Q₂ for the models by PLS and OSC-PLS of bactericidal peptides were 0.84 and 0.546, 0.995 and 0.926, respectively. The value of R₂, Q₂ and RMS in the PLS model of angiotensin-converting enzyme inhibitors were 0.877, 0.838 and 0.361, respectively. Satisfactory results show that, as new amino acid scales, data of VHSEH may be a useful structural expression methodology for the study on quantitative sequence-activity modeling(QSAM) of peptides, due to its many advantages such as plentiful structural information, definite physical and chemical meaning and easy interpretation.

Key words: VHSEH descriptors of amino acid, Peptide, Quantitative sequence-acitivty modeling(QSAM), Partial least squares(PLS)