Differential activity of human, rat, mouse and bacteria glutathione transferase isoenzymes towards 4-nitroquinoline 1-oxide.
The conjugation capacity of 4-nitroquinoline 1-oxide (4-NQO) with GSH by a number of human, rat, mouse and bacteria glutathione transferases (GSTs) was investigated. Pi and mu classes GSTs exhibited maximum conjugation capacity. Alpha class glutathione transferases as well as bacteria glutathione transferases were found to be unable to conjugate GSH to 4-NQO. The Km values as well as the catalytic efficiency (Kcat/Km) for most of the GSTs investigated were also determined. Mouse liver GST MIII (class mu) was the most efficient of the various isoenzymes tested. Its Kcat/Km value was 162 times higher than that of mouse liver GST MI (class alpha). The relatively high catalytic efficiency exhibited by GST-alpha (class pi) is prevalently due to its low affinity for 4-NQO.
Aceto
A
A
Istituto di Scienze Biochimiche, Facolta' di Medicina, Universita' G. D'Annunzio, Chieti, Italy.
Di Ilio
C
C
Lo Bello
M
M
Bucciarelli
T
T
Angelucci
S
S
Federici
G
G
D015112:4-Nitroquinoline-1-oxide / Q000378:metabolism*; D000818:Animals; D004137:Dinitrochlorobenzene / Q000378:metabolism; D005982:Glutathione Transferase / Q000502:physiology*; D006801:Humans; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000378:metabolism*; D051379:Mice; D051381:Rats; D012044:Regression Analysis
D004137:Dinitrochlorobenzene; D007527:Isoenzymes; D015112:4-Nitroquinoline-1-oxide; D005982:Glutathione Transferase