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 th...

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Published inBiochemical journal Vol. 271; no. 2; pp. 559 - 562
Main Authors Bakker, A V, Jung, S, Spencer, R W, Vinick, F J, Faraci, W S
Format Journal Article
LanguageEnglish
Published England 15.10.1990
Subjects
Animals
Brain - enzymology
Dipeptides - metabolism
Dipeptides - pharmacology
Endopeptidases - metabolism
Humans
Kinetics
Mice
Serine Endopeptidases
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Summary: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.
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ISSN:0264-6021
1470-8728
DOI:10.1042/bj2710559