title: Characterization of affinity-purified isoforms of Acinetobacter calcoaceticus Y1 glutathione transferases.
abstract: Glutathione transferases (GST) were purified from locally isolated bacteria, Acinetobacter calcoaceticus Y1, by glutathione-affinity chromatography and anion exchange, and their substrate specificities were investigated. SDS-polyacrylamide gel electrophoresis revealed that the purified GST resolved into a single band with a molecular weight (MW) of 23 kDa. 2-dimensional (2-D) gel electrophoresis showed the presence of two isoforms, GST1 (pI 4.5) and GST2 (pI 6.2) with identical MW. GST1 was reactive towards ethacrynic acid, hydrogen peroxide, 1-chloro-2,4-dinitrobenzene, and trans,trans-hepta-2,4-dienal while GST2 was active towards all substrates except hydrogen peroxide. This demonstrated that GST1 possessed peroxidase activity which was absent in GST2. This study also showed that only GST2 was able to conjugate GSH to isoproturon, a herbicide. GST1 and GST2 were suggested to be similar to F0KLY9 (putative glutathione S-transferase) and F0KKB0 (glutathione S-transferase III) of Acinetobacter calcoaceticus strain PHEA-2, respectively.
authors.affiliation: Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Chin-Soon
authors.initials: CS
authors.lastname: Chee
authors.affiliation: Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia ; Centre for Research in Biotechnology for Agriculture (CEBAR), University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Irene Kit-Ping
authors.initials: IK
authors.lastname: Tan
authors.affiliation: Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Zazali
authors.initials: Z
authors.lastname: Alias
mesh_terms: D016954:Acinetobacter calcoaceticus / Q000201:enzymology*; D000595:Amino Acid Sequence; D002846:Chromatography, Affinity / Q000379:methods*; D015180:Electrophoresis, Gel, Two-Dimensional; D005982:Glutathione Transferase / Q000737:chemistry / Q000302:isolation & purification*; D007527:Isoenzymes / Q000737:chemistry / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D007527:Isoenzymes; D005982:Glutathione Transferase