Porcine glutathione transferase Alpha 2-2 is a human GST A3-3 analogue that catalyses steroid double-bond isomerization.
A primary role of GSTs (glutathione transferases) is detoxication of electrophilic compounds. In addition to this protective function, hGST (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 hGST A3-3 in steroidogenic tissues. An analogous GST with high steroid isomerase activity has so far not been found in any other biological species. In the present study, we characterized a Sus scrofa (pig) enzyme, pGST A2-2, displaying high steroid isomerase activity. High levels of pGST A2-2 expression were found in ovary, testis and liver. In its functional properties, other than steroid isomerization, pGST A2-2 was most similar to hGST A3-3. The properties of the novel porcine enzyme lend support to the notion that particular GSTs play an important role in steroidogenesis.
Fedulova
Natalia
N
Department of Biochemistry and Organic Chemistry, Uppsala University, Biomedical Center, Box 576, SE-75123 Uppsala, Sweden.
Raffalli-Mathieu
Françoise
F
Mannervik
Bengt
B
D000595:Amino Acid Sequence; D000818:Animals; D002384:Catalysis; D005260:Female; D005982:Glutathione Transferase / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D007527:Isoenzymes / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008969:Molecular Sequence Data; D010053:Ovary / Q000378:metabolism; D016415:Sequence Alignment; D013251:Steroid Isomerases / Q000737:chemistry* / Q000378:metabolism; D013552:Swine; D013737:Testis / Q000378:metabolism
D007527:Isoenzymes; D005982:Glutathione Transferase; C495975:glutathione S-transferase A3-3, human; C119995:glutathione S-transferase alpha; D013251:Steroid Isomerases