Slow tight-binding inhibition of prolyl endopeptidase by benzyloxycarbonyl-prolyl-prolinal.
Prolyl endopeptidase is a serine proteinase that specifically cleaves peptides on the carboxy side of proline residues. Wilk & Orlowski [(1983) J. Neurochem. 41, 69-75] have shown that benzyloxycarbonyl-prolyl-prolinal (Z-prolyl-prolinal) is a potent inhibitor of prolyl endopeptidase. We show that Z-prolyl-prolinal is a slow-binding inhibitor of mouse brain prolyl endopeptidase with Ki 0.35 +/- 0.05 nM. Kinetic analysis indicates that the mechanism is a simple, but slow, reversible equilibrium between free and bound enzyme (E + I in equilibrium EI) with rate constants for association (kon) and dissociation (koff) of 1.6 X 10(5) M-1.s-1 and approx. 4 X 10(-5) s-1 respectively. Slow-binding inhibition is dependent on the presence of the aldehyde group since the alcohol (Z-prolyl-prolinol) is a rapid and 50,000-fold poorer inhibitor (Ki 19 microM). Prolyl endopeptidase from human brain is also inhibited by Z-prolyl-prolinal with kinetics similar to those of the mouse brain enzyme.
Bakker
A V
AV
Department of Medicinal Chemistry, Pfizer Inc., Groton, CT 06340.
Jung
S
S
Spencer
R W
RW
Vinick
F J
FJ
Faraci
W S
WS
D000818:Animals; D001921:Brain / Q000201:enzymology*; D004151:Dipeptides / Q000378:metabolism / Q000494:pharmacology*; D010450:Endopeptidases / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D051379:Mice; D000085822:Prolyl Oligopeptidases; D012697:Serine Endopeptidases
D004151:Dipeptides; C038541:N-benzyloxycarbonylprolylprolinal; D010450:Endopeptidases; D012697:Serine Endopeptidases; C000705287:PREPL protein, human; D000085822:Prolyl Oligopeptidases