The isolation of a fetal rat liver glutathione S-transferase isoenzyme with high glutathione peroxidase activity.
A previously uncharacterized glutathione S-transferase isoenzyme which is absent from normal adult rat livers has been isolated from fetal rat livers. The enzyme was purified using a combination of affinity chromatography, CM-cellulose column chromatography and chromatofocusing. It is composed of two non-identical subunits, namely, subunit Yc (Mr 28,000) and a subunit (Mr 25,500) recently reported by us to be uniquely present in fetal rat livers and which we now refer to as subunit 'Yfetus'. The enzyme which we term glutathione S-transferase YcYfetus has an isoelectric point of approx. 8.65 and has glutathione S-transferase activity towards a number of substrates. The most significant property of the fetal isozyme is its high glutathione peroxidase activity towards the model substrate cumene hydroperoxide. We suggest that this isozyme serves a specific function in protecting fetuses against the possible teratogenic effects of organic peroxides.
Scott
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Department of Medicine, University of Cape Town Medical School, Observatory, Republic of South Africa.
Kirsch
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D000596:Amino Acids / Q000032:analysis; D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D005333:Fetus / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism*; D005982:Glutathione Transferase / Q000302:isolation & purification*; D007525:Isoelectric Focusing; D007527:Isoenzymes / Q000302:isolation & purification*; D008099:Liver / Q000196:embryology* / Q000201:enzymology; D008970:Molecular Weight; D051381:Rats; D013379:Substrate Specificity
D000596:Amino Acids; D007527:Isoenzymes; D005979:Glutathione Peroxidase; D005982:Glutathione Transferase