The Preparation And Propertyies Of Similar ACE Inhibitory Peptides

Angiotensin convert enzyme （ACE） plays an important physiologic role in the bloodpressure regulation, ACE inhibitory peptides can effective inhibit it’s activity then lower theblood pressure, and has no side effects. So ACE inhibitory peptides has been the hotspot inthe physiological bioactive peptides. Studing on the interactions of ACE inhibitory peptideswith DNA and determine it’s vitro inhibitory activity are not only importance for clarifing thestructure and function of DNA, but also useful for understanding the mechanism of ACEinhibitory peptides’ action and designing ACE inhibitory drug.In this thesis, eight similar ACE inhibitory peptides were synthesized by solid phasesynthesis. The crude peptide product were analyzedd and separated by RP-HPLC, thencharacted by ESI-MS.The interaction of seven similar ACE inhibitory peptides with DNA had been studised byutilizing fluorescence, ultraviolet spectroscopy and voscosity method. The result showed thatYKYY, WVYY, YYAAY, YGAYAP, YGAYKP, YGAYVY inserted in DNA with the mode ofthe “partial”（or the “nonclassical”）, and YYKAF interact with DNA by electrostatic binding.According to the Scatchard equation, the binding constant of YKYY, WVYY, YYAAY,YYKAF, YGAYAP, YGAYKP, YGAYVY with DNA were calculated to be K=1.0×10⁴L·mol^-1;8.3×10³L·mol^-1,2.7×10⁵L·mol^-1,2.78×10³L·mol^-1,1.7×10³L·mol^-1,3.9×10³L·mol^-1,7.61×10⁴L·mol^-1. Those data show that the interaction of the peptides with DNA may be stronger whenthe peptides has more polar aromatic amino acids.The eight similar ACE inhibitory peptides in vitro were determined by RP-HPLC. Theresults show that eight similar ACE inhibitory peptides all have the function of inhibit theactivity of ACE, The more aromic group the peptides have, the stronger the peptides inhibitACE’s activity. Peptides which have more hydrophobic amino and long branched amino havestronger ability of inhibit the activity of ACE. when the N-terminal amino acid of peptides issame, the peptides’s ability of inhibit ACE’s activity change obviouly with the change of thekinds of it’s C-terminal amino acid.