Inhibition by inorganic anions of glutathione S-transferases from insect and mammalian sources.
Glutathione S-transferases 1-1, 3-3, 3-4 and 4-4 from rat liver and the major glutathione S-transferase from the wax moth (Galleria mellonella) are all inhibited by several simple inorganic anions. For each of 3-3, 3-4 and the insect enzyme, the order of inhibitory potency was ClO4- greater than or equal to SCN- greater than I- greater than NO3- greater than Br-. A more limited range of anions was tested on the isoenzymes 1-1 and 4-4, but the same trend was apparent. Values for Ki ranged from about 200 mM for Cl- to 6 mM for SCN- in the case of the insect enzyme and from 50 mM for Br- to 0.3 mM for SCN- for the rat isoform 3-3. Acetate, F-, SO4(2-) and PO4(3-) were not found to have significant inhibitory properties. The mode of inhibition was characterized as non-competitive in the case of the insect enzyme and rat transferase 1-1, whereas the mode of inhibition was partially non-competitive in the case of the rat isoforms 3-3, 3-4 and 4-4.
Clark
A G
AG
School of Biological Sciences, Victoria University of Wellington, New Zealand.
Hamilton
J F
JF
Marshall
S N
SN
D000818:Animals; D000838:Anions / Q000494:pharmacology*; D001965:Bromides / Q000494:pharmacology; D002704:Chlorates / Q000494:pharmacology; D002712:Chlorides / Q000494:pharmacology; D005982:Glutathione Transferase / Q000037:antagonists & inhibitors*; D007454:Iodides / Q000494:pharmacology; D007527:Isoenzymes / Q000037:antagonists & inhibitors*; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008297:Male; D009036:Moths / Q000201:enzymology*; D009566:Nitrates / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013045:Species Specificity; D013861:Thiocyanates / Q000494:pharmacology
D000838:Anions; D001965:Bromides; D002704:Chlorates; D002712:Chlorides; D007454:Iodides; D007527:Isoenzymes; D009566:Nitrates; D013861:Thiocyanates; D005982:Glutathione Transferase