title: [Active centers of gamma-glutamyltransferase in the aerosol OT reverse micellar system in octane by an inhibitor analysis method].
abstract: Regulation of the supramolecular structure and catalytic activity of the heterodimeric enzyme gamma-glutamyltransferase in the system of Aerosol OT reversed micelles in octane was studied. Variation of the hydration degree causes a reversible dissociation of the enzyme to the light and heavy subunits, both possessing the catalytic activity. The subunits were separated on the preparative scale in the reversed micelle system using ultracentrifugation. The active centres of gamma-glutamyltransferase were studied using the enzyme's irreversible inhibitor AT-125 (L-(alpha S, 5S)-alpha-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid). It is shown that the separation of the gamma-glutamyltransferase subunits results in "opening" of a new active centre in the heavy subunit, whereas in the enzyme's dimeric form this centre is masked and not accessible to the inhibitor's molecule. The kinetic and inhibitor analysis data indicate that the active centres in the light and heavy subunits are similar.
authors.forename: S I
authors.initials: SI
authors.lastname: Nametkin
authors.forename: A V
authors.initials: AV
authors.lastname: Kabanov
authors.forename: A V
authors.initials: AV
authors.lastname: Levashov
mesh_terms: D001665:Binding Sites; D002384:Catalysis; D004143:Dioctyl Sulfosuccinic Acid / Q000737:chemistry*; D007555:Isoxazoles / Q000494:pharmacology; D007700:Kinetics; D008823:Micelles; D005723:gamma-Glutamyltransferase / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D007555:Isoxazoles; D008823:Micelles; D004143:Dioctyl Sulfosuccinic Acid; D005723:gamma-Glutamyltransferase; C006303:acivicin
vernacular_title: Issledovanie aktivny6kh tsentrov gamma-glutamiltransferazy v sistem obrashchennykh mitsell aérozolia OT v oktane metodom ingibitornogo analiza.