Properties of the prolyl oligopeptidase homologue from Pyrococcus furiosus.
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.
Juhász
Tünde
T
Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, Budapest.
Szeltner
Zoltán
Z
Polgár
László
L
D001483:Base Sequence; D002850:Chromatography, Gel; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D000085822:Prolyl Oligopeptidases; D020027:Pyrococcus furiosus / Q000201:enzymology*; D012697:Serine Endopeptidases / Q000378:metabolism*; D013379:Substrate Specificity
D017931:DNA Primers; D012697:Serine Endopeptidases; D000085822:Prolyl Oligopeptidases