Properties of the prolyl oligopeptidase homologue from Pyrococcus furiosus |
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Authors: | Juhász Tünde Szeltner Zoltán Polgár László |
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Affiliation: | Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, Budapest. |
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Abstract: | Prolyl oligopeptidase (POP), the paradigm of a serine peptidase family, hydrolyses peptides, but not proteins. The thermophilic POP from Pyrococcus furiosus (Pfu) appeared to be an exception, since it hydrolysed large proteins. Here we demonstrate that the Pfu POP does not display appreciable activity against azocasein. The autolysis observed earlier was an artefact. We have also found that the pH-rate profile is different from that of the mammalian enzyme and the low pK(a) extracted from the curve represents the ionization of the catalytic histidine. We conclude that some oligopeptidases may be true endopeptidases, cleaving at disordered segments of proteins, but with very low efficacy. |
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Keywords: | POP, prolyl oligopeptidase Pfu, Pyrococcus furiosus PCR, polymerase chain reaction EDTA, ethylenediaminetetraacetatic acid SDS-PAGE, sodium dodecyl sulfate polyacrylamide gel electrophoresis Z, benzyloxycarbonyl Nap, 2-naphthylamine Nan, 4-nitroanilide |
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