title: Purification and characterization of an esterase hydrolyzing monoalkyl phthalates from Micrococcus sp. YGJ1.
abstract: An esterase that specifically hydrolyzes medium-chain (C(3)-C(5)) monoalkyl phthalates was purified from phthalate-grown Micrococcus sp. YGJ1. The enzyme activity was split into two fractions by hydrophobic chromatography on Phenyl Sepharose, and the enzymes were purified to homogeneity from each fraction. The purified enzymes showed similar properties with respect to molecular mass (60 kDa), subunit molecular mass (27 kDa), N-terminal amino acid sequence, optimal pH (about 7.5), temperature-dependence, substrate specificity, and inhibitor susceptibility. The enzymes showed no activity toward various dialkyl phthalates or aliphatic carboxyl esters. 2-Mercaptoethanol effectively protected the enzymes from spontaneous inactivation. Diethylpyrocarbonate, p-chloromercuribenzoate, Hg(2+), and Cu(2+) strongly inhibited the enzymes, while phenylmethylsulfonyl fluoride produced weak inhibition, and various metal chelating reagents were ineffective. These findings show that the enzymes bear a close resemblance to the putative phthalate ester hydrolase (PehA) of Arthrobacter keyseri 12B.
authors.affiliation: Department of Biomolecular Science, Faculty of Engineering, Gifu University, Gifu 501-1193, Japan. maruyama@cc.gifu-u.ac.jp
authors.forename: Kiyofumi
authors.initials: K
authors.lastname: Maruyama
authors.forename: Keiichi
authors.initials: K
authors.lastname: Akita
authors.forename: Chikako
authors.initials: C
authors.lastname: Naitou
authors.forename: Masahiko
authors.initials: M
authors.lastname: Yoshida
authors.forename: Toshiki
authors.initials: T
authors.lastname: Kitamura
mesh_terms: D002265:Carboxylic Ester Hydrolases / Q000737:chemistry* / Q000302:isolation & purification*; D008837:Micrococcus / Q000201:enzymology*; D010795:Phthalic Acids / Q000737:chemistry*; D013379:Substrate Specificity
chemical_list: D010795:Phthalic Acids; D002265:Carboxylic Ester Hydrolases