Abstract
A spin-labelled analogue (sl-glutathione) has been used in order to characterize the active site of human placenta glutathione transferase π. The sl-glutathione shows a competitive inhibition towards glutathione (Ki = 14 μM). Binding of sl-glutathione to the enzyme, followed by electron paramagnetic resonance spectroscopy, gives a Kd of 3 μM and two identical binding sites for dimeric unit. Inhibition of the enzyme, by modification of the Cys-47 residue, completely prevents the binding of sl-glutathione. The same results are obtained by monitoring the binding of glutathione by means of fluorescence spectroscopy. It is concluded that integrity of the thiolate of Cys-47 is necessary to maintain an active conformation of the enzyme able to efficiently bind glutathione into the active site.
Original language | English |
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Pages (from-to) | 265-268 |
Number of pages | 4 |
Journal | Biochimica et Biophysica Acta (BBA)/Protein Structure and Molecular |
Volume | 1122 |
Issue number | 3 |
DOIs | |
Publication status | Published - Aug 21 1992 |
Keywords
- EPR
- G-site
- Glutathione
- GSH transferase π
- Spin-labelled glutathione
ASJC Scopus subject areas
- Biochemistry
- Biophysics
- Molecular Biology
- Structural Biology