Characterization of a novel acylaminoacyl peptidase with hexameric structure and endopeptidase activity
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Tartalom: http://www.sciencedirect.com/science/article/pii/S1570963909000624
Archívum: REAL
Gyűjtemény: Status = Published
Subject = Q Science / természettudomány: QD Chemistry / kémia: QD05 Crystallography / kristálytan
Type = Article
Cím:
Characterization of a novel acylaminoacyl peptidase with hexameric structure and endopeptidase activity
Létrehozó:
Szeltner, Zoltán
Kiss, András
Domokos, Klarissza
Harmat, Veronika
Náray-Szabó, Gábor
Polgár, László
Dátum:
2009
Téma:
QD05 Crystallography / kristálytan
Tartalmi leírás:
We have overexpressed in E. coli, purified and investigated the kinetic, thermodynamic and biophysical properties of an acylaminoacyl peptidase (AAP), from the thermophile Pyrococcus horikoshii (PhAAP). It was shown that the electrostatic environment of the catalytic site of PhAAP substantially influenced the pH dependence of the specificity rate constant (kcat/Km). However, 0.3 M NaCl, which depressed the electrostatic effects, simplified the complex pH-rate profile. The rate of formation of the enzyme–substrate complex (k1) was obtained from a non-linear Arrhenius plot. The lack of substrate leaving group effects indicated that k1 is the rate determining step in the catalysis. DSC and CD measurements demonstrated that PhAAP displayed a stable structure in the catalytically competent pH range. It was shown that PhAAP is not just an acylaminoacyl peptidase, but it also has an endopeptidase activity and so differs from the mammalian AAPs. Size exclusion chromatography with PhAAP revealed a hexameric structure, which is unique among the known members of the prolyl oligopeptidase family that includes AAPs and suggests that its cellular function may be different from that of the dimeric AAP also found in the same organism.
Típus:
Article
PeerReviewed
Formátum:
application/pdf
Azonosító:
Szeltner, Zoltán and Kiss, András and Domokos, Klarissza and Harmat, Veronika and Náray-Szabó, Gábor and Polgár, László (2009) Characterization of a novel acylaminoacyl peptidase with hexameric structure and endopeptidase activity. Biochimica et Biophysica Acta, 1794 (8). pp. 1204-1210. ISSN 1570-9639
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