A new set of descripotors called molecular electro-negativity edge vector (MEEV) were developed from the primary structures of peptides, in order to describe the peptide structure, based on the distance between atoms and the electro-negativity of each atom. Several models of quantitative structure activity relationship are proposed for 58 dipeptides (angiotensin converting enzyme inhibitors) by the multiple linear regression method. In order to explain the ability to characterize the molecular structure of polypeptides, a model investigation was carried out on the QSAR of pentapeptides. The results showed that MEEV exhibited both excellent structural selectivity and good estimation of activity. MEEV is easy to use and generally applicabled. There fore, it should be very useful in strutural characterization and activity prediction of biological molecules.

Key words: OLIGOPEPTIDE, STRUCTURE PARAMETER, ENZYME INHIBITOR, ANGIOTENSIN, POLYPEPTIDE, BRADYKININ, SYNERGISTS, DIPEPTIDE, QUANTITATIVE STRUCTURE ACTIVITY RELATIONSHIP