Porcine glutathione transferase alpha 2-2 is a human GST A3-3 analogue catalyzing steroid double-bond isomerization

Natalia Fedulova , Françoise Raffalli-Mathieu , Bengt Mannervik (1)

1 Biochemistry and Organic Chemistry

A primary role of glutathione transferases (GSTs) is detoxication of electrophilic compounds. In addition to this protective function human GST A3-3, a member of the Alpha class of soluble GSTs, has prominent steroid double-bond isomerase activity. The isomerase reaction is an obligatory step in the biosynthesis of steroid hormones, indicating a special role of human GST A3-3 in steroidogenic tissues. An analogous GST with high steroid isomerase activity has not so far been found in any other biological species. In the present investigation we characterize a Sus scrofa (pig) enzyme, pGSTA2-2, displaying high steroid isomerase activity. High levels of pGSTA2-2 expression were found in ovary, testis, and liver. Also in functional properties other than steroid isomerization pGSTA2-2 was similar to the human enzyme hGSTA3-3. Other human GSTs were more divergent in their functions. The properties of the novel porcine enzyme lend support to the notion that particular GSTs play an important role in steroidogenesis.

Mots clés: Life Sciences

Natalia Fedulova, Françoise Raffalli-Mathieu, Bengt Mannervik. Porcine glutathione transferase alpha 2-2 is a human GST A3-3 analogue catalyzing steroid double-bond isomerization. Biochemical Journal, 2010, 431 (1), pp.159-167. ⟨10.1042/BJ20100839⟩. ⟨hal-00517255⟩