Szeltner_2002_J.Biol.Chem_277_44597

Reference

Title : Substrate-dependent competency of the catalytic triad of prolyl oligopeptidase - Szeltner_2002_J.Biol.Chem_277_44597
Author(s) : Szeltner Z , Rea D , Juhasz T , Renner V , Mucsi Z , Orosz G , Fulop V , Polgar L
Ref : Journal of Biological Chemistry , 277 :44597 , 2002
Abstract :

Prolyl oligopeptidase, a serine peptidase unrelated to trypsin and subtilisin, is implicated in memory disorders and is an important target of drug design. The catalytic competence of the Asp(641) residue of the catalytic triad (Ser(554), Asp(641), His(680)) was studied using the D641N and D641A variants of the enzyme. Both variants displayed 3 orders of magnitude reduction in k(cat)/K(m) for benzyloxycarbonyl-Gly-Pro-2-naphthylamide. Using an octapeptide substrate, the decrease was 6 orders of magnitude, whereas with Z-Gly-Pro-4-nitrophenyl ester there was virtually no change in k(cat)/K(m). This indicates that the contribution of Asp(641) is very much dependent on the substrate-leaving group, which was not the case for the classic serine peptidase, trypsin. The rate constant for benzyloxycarbonyl-Gly-Pro-thiobenzylester conformed to this series as demonstrated by a method designed for monitoring the hydrolysis of thiolesters in the presence of thiol groups. Alkylation of His(680) with Z-Gly-Pro-CH(2)Cl was concluded with similar rate constants for wild-type and D641A variant. However, kinetic measurements with Z-Gly-Pro-OH, a product-like inhibitor, indicated that the His(680) is not accessible in the enzyme variants. Crystal structure determination of these mutants revealed subtle perturbations related to the catalytic activity. Many of these observations show differences in the catalysis between trypsin and prolyl oligopeptidase.

PubMedSearch : Szeltner_2002_J.Biol.Chem_277_44597
PubMedID: 12228249
Gene_locus related to this paper: pig-ppce

Related information

Inhibitor Sin-Gly-Pro
Gene_locus Sin-Gly-Pro    pig-ppce
Structure Sin-Gly-Pro    pig-ppce    1O6F    1O6G

Citations formats

Szeltner Z, Rea D, Juhasz T, Renner V, Mucsi Z, Orosz G, Fulop V, Polgar L (2002)
Substrate-dependent competency of the catalytic triad of prolyl oligopeptidase
Journal of Biological Chemistry 277 :44597

Szeltner Z, Rea D, Juhasz T, Renner V, Mucsi Z, Orosz G, Fulop V, Polgar L (2002)
Journal of Biological Chemistry 277 :44597