title: Glutamate cysteine ligase (GCL) in the freshwater bivalve Unio tumidus: impact of storage conditions and seasons on activity and identification of partial coding sequence of the catalytic subunit.
abstract: Glutamate cysteine ligase (GCL; EC 6.3.2.2) is the first enzyme involved in the synthesis of glutathione. A HPLC method with fluorimetric detection was used to measure GCL activity in the gills and the digestive gland of the freshwater bivalve, Unio tumidus. Storage conditions were optimized in order to prevent decrease of GCL activity and consisted in freezing the cytosolic fraction in the presence of protease (1 mM phenylmethylsulfonic fluoric acid) and gamma-glutamyltranspeptidase (1 mM L-serine borate mixture and 0.5 mM acivicin) inhibitors. Seasonal variations of activity in the digestive gland and to a lesser extent in the gills were found with activity increasing in spring compared to winter. No sex differences were revealed. The GCL coding sequence was identified using degenerated primers designed in the highly conserved regions of the catalytic subunit of GCL. The partial sequence identified encoded for 121 amino acids. The comparison of the identified partial coding sequence of U. tumidus with those available from vertebrates and invertebrates indicated that GCL sequence was highly conserved.
authors.affiliation: Laboratoire E. S. E. Ecotoxicité, Santé Environnementale - CNRS UMR 7146, Université, Paul Verlaine, rue du Général Delestraint, 57070 Metz, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Coffinet
authors.forename: Carole
authors.initials: C
authors.lastname: Cossu-Leguille
authors.forename: François
authors.initials: F
authors.lastname: Rodius
authors.forename: Paule
authors.initials: P
authors.lastname: Vasseur
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D020134:Catalytic Domain / Q000235:genetics*; D004064:Digestive System / Q000378:metabolism; D005880:Gills / Q000378:metabolism; D005721:Glutamate-Cysteine Ligase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics*; D012621:Seasons; D013997:Time Factors; D049881:Unio / Q000033:anatomy & histology / Q000166:cytology / Q000201:enzymology*
chemical_list: D005721:Glutamate-Cysteine Ligase