Specific inhibition of endopeptidase 24.16 by dipeptides.
The inhibitory effect of various dipeptides on the neurotensin-degrading metallopeptidase, endopeptidase 24.16, was examined. These dipeptides mimick the Pro10-Tyr11 bond of neurotensin that is hydrolyzed by endopeptidase 24.16. Among a series of Pro-Xaa dipeptides, the most potent inhibitory effect was elicited by Pro-Ile (Ki approximately 90 microM) with Pro-Ile greater than Pro-Met greater than Pro-Phe. All the Xaa-Tyr dipeptides were unable to inhibit endopeptidase 24.16. The effect of Pro-Ile on several purified peptidases was assessed by means of fluorigenic assays and HPLC analysis. A 5 mM concentration of Pro-Ile does not inhibit endopeptidase 24.11, endopeptidase 24.15, angiotensin-converting enzyme, proline endopeptidase, trypsin, leucine aminopeptidase, pyroglutamyl aminopeptidase I and carboxypeptidase B. The only enzyme that was affected by Pro-Ile was carboxypeptidase A, although it was with a 50-fold lower potency (Ki approximately 5 mM) than for endopeptidase 24.16. By means of fluorimetric substrates with a series of hydrolysing activities, we demonstrate that Pro-Ile can be used as a specific inhibitor of endopeptidase 24.16, even in a complex mixture of peptidase activities such as found in whole rat brain homogenate.
Dauch
P
P
Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Sophia Antipolis, Valbonne, France.
Vincent
J P
JP
Checler
F
F
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000201:enzymology; D002851:Chromatography, High Pressure Liquid; D004151:Dipeptides / Q000494:pharmacology*; D006868:Hydrolysis; D008297:Male; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D009496:Neurotensin / Q000378:metabolism; D011480:Protease Inhibitors / Q000302:isolation & purification; D051381:Rats; D011919:Rats, Inbred Strains
D004151:Dipeptides; D011480:Protease Inhibitors; D009496:Neurotensin; D008666:Metalloendopeptidases; C062316:neurolysin