A spin-labelled analogue of glutathione (sl-glutathione) has been used in order to characterize the active site of human placenta glutathione transferasc pi. The sl-glutathione shows a competitive inhibition towards glutathione (K(i) = 14-mu-M). Binding of sl-glutathione to the enzyme, followed by electron paramagnetic resonance spectroscopy, gives a K(d) of 3-mu-M 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 Cvs-47 is necessary to maintain an active conformation of the enzyme able to efficiently bind glutathione into the active site.

Caccuri, A.m., Polizio, F., Piemonte, F., Tagliatesta, P., Federici, G., Desideri, A. (1992). Investigation of the active site of human placenta glutathione transferase pi by means of a spin-labelled glutathione analogue. BIOCHIMICA ET BIOPHYSICA ACTA, 1122(3), 265-268 [10.1016/0167-4838(92)90402-Y].

Investigation of the active site of human placenta glutathione transferase pi by means of a spin-labelled glutathione analogue

CACCURI, ANNA MARIA;POLIZIO, FRANCESCA;TAGLIATESTA, PIETRO;FEDERICI, GIORGIO;DESIDERI, ALESSANDRO
1992-01-01

Abstract

A spin-labelled analogue of glutathione (sl-glutathione) has been used in order to characterize the active site of human placenta glutathione transferasc pi. The sl-glutathione shows a competitive inhibition towards glutathione (K(i) = 14-mu-M). Binding of sl-glutathione to the enzyme, followed by electron paramagnetic resonance spectroscopy, gives a K(d) of 3-mu-M 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 Cvs-47 is necessary to maintain an active conformation of the enzyme able to efficiently bind glutathione into the active site.
1992
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore BIO/10 - BIOCHIMICA
English
Con Impact Factor ISI
GSH transferase-PI; G-site; spin-labeled glutathione; EPR; glutathione
Caccuri, A.m., Polizio, F., Piemonte, F., Tagliatesta, P., Federici, G., Desideri, A. (1992). Investigation of the active site of human placenta glutathione transferase pi by means of a spin-labelled glutathione analogue. BIOCHIMICA ET BIOPHYSICA ACTA, 1122(3), 265-268 [10.1016/0167-4838(92)90402-Y].
Caccuri, Am; Polizio, F; Piemonte, F; Tagliatesta, P; Federici, G; Desideri, A
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/54152
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