title: Retro-inverso concept applied to the complete inhibitors of enkephalin-degrading enzymes.
abstract: Peptide retro-inverso modification was applied to the complete hydroxamate inhibitors of the three zinc metallopeptidases (neutral endopeptidase 24-11 (NEP, EC 3.4.24.11), aminopeptidase N (APN, EC 3.4.11.2), and a dipeptidylaminopeptidase (DAP) involved in the in vitro enkephalin degradation by brain tissues. Compounds corresponding to the general formula RN(OH)CO(CH2)nCH(CH2Ph)NHCOCH(R')COOH (n = 0, 1) were synthesized. In the first series of inhibitors (n = 0), the "retro-inverso" modification induced a large decrease in inhibitory potency for NEP as compared to that of the parent compounds. In contrast, the presence of a methylene group between the hydroxamate and CH alpha in the second series (n = 1) led to derivatives with inhibitory potencies in the nanomolar range, similar to their analogues with a natural amide bond. On the other hand, the retro-inverso modification led to a slight improvement in the inhibition of DAP and APN, in the first series of inhibitors, while the inverse result occurred in the second series. Thus, compounds containing an alpha-amino acid moiety in P'1 position behave as weak inhibitors of the three enzymes, with IC50 values in the micromolar range, and compounds bearing a beta-amino acid moiety in the same position are more specific than the parent compounds for NEP inhibition.
mesh_terms: D000626:Aminopeptidases / Q000037:antagonists & inhibitors*; D000818:Animals; D001921:Brain / Q000201:enzymology; D018826:CD13 Antigens; D055598:Chemical Phenomena; D002621:Chemistry; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000037:antagonists & inhibitors*; D006877:Hydroxamic Acids / Q000138:chemical synthesis / Q000494:pharmacology*; D007668:Kidney / Q000201:enzymology; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors*; D008968:Molecular Conformation; D015260:Neprilysin; D011817:Rabbits; D051381:Rats; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D013552:Swine
chemical_list: D006877:Hydroxamic Acids; D000626:Aminopeptidases; D018826:CD13 Antigens; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D008666:Metalloendopeptidases; D015260:Neprilysin