title: Alteration of metal ions improves the activity and thermostability of aminoacylase from hyperthermophilic archaeon Pyrococcus horikoshii.
abstract: Recombinant L-aminoacylase (PhoACY) from a hyperthermophilic archeon, Pyrococcus horikoshii, is a zinc-containing metalloenzyme. When the zinc was substituted by Mn(2+) or Ni(2+), its specific activity was significantly increased with acetyl-L-methionine as a substrate. The thermostability of PhoACY was improved when it was incubated with 1 mM Zn(2+), Mn(2+) or Ni(2+). The enzyme with external Zn(2+) addition had no significant loss of the activity when held at 90 degrees C for up to 12 h and moreover had more than a 10-fold longer half-life even at 100 degrees C, compared to the enzyme without Zn(2+) addition. A thermostable structure of the enzyme associated with zinc binding is described based on differential scanning calorimetry.
authors.affiliation: Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan.
authors.forename: Motomu
authors.initials: M
authors.lastname: Nishioka
authors.forename: Koichi
authors.initials: K
authors.lastname: Tanimoto
authors.forename: Noriko
authors.initials: N
authors.lastname: Higashi
authors.forename: Harumi
authors.initials: H
authors.lastname: Fukada
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ishikawa
authors.forename: Masahito
authors.initials: M
authors.lastname: Taya
mesh_terms: D000581:Amidohydrolases / Q000378:metabolism*; D002152:Calorimetry, Differential Scanning; D004795:Enzyme Stability / Q000187:drug effects; D008670:Metals / Q000494:pharmacology*; D043902:Pyrococcus horikoshii / Q000201:enzymology*; D013696:Temperature
chemical_list: D008670:Metals; D000581:Amidohydrolases; C019672:aminoacylase I