The effect of external electric field (EEF) of 5.14, 25.70, and 51.40 MV/cm upon Cys-Asn-Ser, Glu-Arg-Leu, Glu-Cys-Glc, Ser-Asp-Leu, Ser-Glu-Met tripeptide inner salts was simulated involving HyperChem 8.0 software together with the AM1 method for optimization of the molecules' conformation. The reaction to EEF is diverse and specific to particular peptides. EEF stimulated an increase in the positive charge density on the hydrogen atoms of the N(+)H3, peptide bond NH, NH2, and COOH groups as well decrease in the negative charge density on the oxygen atoms of the peptide bond carbonyl groups. Thus, EEF could control behavior and action of tripeptides, such as an increase in their catalytic activity.