Naslov
Effect of glutathione, gluthatione sulphonate and S-hexylglutathione on the conformational stability of class pi glutathione S-transferase pGSTP1-1

Autori
Erhardt, Julija ; Dirr, H.

Izvornik
FEBS letters (0014-5793) 391 (1996), 3; 313-316

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
conformational stability ; unfolding ; denaturation ; glutathione s-transferase ; ligand binding ; glutathione

Sažetak
The glutathione S-transferases (GST) are a supergene family of phase II detoxification enzymes which catalyse the S-conjugation between glutathione and an electrophilic substrate, The active site can be divided into two adjacent functional regions, a highly specific G-site for binding the physiological substrate glutathione and a nonspecific H-site for binding nonpolar electrophilic substrates. Equilibrium and kinetic unfolding experiments employing tryptophan fluorescence and enzyme activity measurements were preformed to study the effect of ligand binding to the G-site on the unfolding and stability of the porcine class pi glutathione S-transferase against urea, The presence of glutathione caused a shift in the equilibrium-unfolding curves towards lower urea concentrations and enhanced the first-order rate constant for unfolding suggesting a destabilisation of the pGSTP1-1 structure against urea, The presence of either glutathione sulphonate or S-hexylglutathione, however, produced the opposite effect in that their binding to the G-site appeared to exert a stabilising effect against urea, The binding of these glutathione analogues also reduced significantly the degree of cooperativity of unfolding indicating a possible change in the protein's unfolding pathway. [References: 32]

Izvorni jezik
Engleski

Znanstvena područja
Biologija

POVEZANOST RADA