Journal article

Binding and kinetic mechanisms of the zeta class glutathione transferase

G Ricci, P Turella, F De Maria, G Antonini, L Nardocci, PG Board, MW Parker, MG Carbonelli, G Federici, AM Caccuri

JOURNAL OF BIOLOGICAL CHEMISTRY | AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC | Published : 2004

Abstract

The Zeta class of glutathione transferases (GSTs) has only recently been discovered and hence has been poorly characterized. Here we investigate the substrate binding and kinetic mechanisms of the human Zeta class GSTZ1c-1c by means of pre-steady state and steady-state experiments and site-directed mutagenesis. Binding of GSH occurs at a very low rate compared with that observed for the more recently evolved GSTs (Alpha, Mu, and Pi classes). Moreover, the single step binding mechanism observed in this enzyme is reminiscent of that found for the Theta class enzyme, whereas the Alpha, Mu, and Pi classes have adopted a multistep binding mechanism. Replacement of Cys16 with Ala increases the rat..

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