Subcellular distribution of glutathione S-transferase in Chinese fetal liver

Subcellular fractions were isolated from Chinese fetal liver at 4-8 months of age for the determination of glutathione S-transferase (GST). Using 1-chloro-2,4-dinitrobenzene (CDNB) as substrate, GST activity was found to be 66 +/- 34 nmol/(min.mg protein), mainly in the cytosol. The GST activities were detected principally in microsomes and their values were 66 +/- 31 and 144 +/- 83 nmol/(min.mg protein), respectively, when assayed with p-nitrobenzyl chloride (PNB) and ethacrynic acid (EA) as substrates. There were no age and sex-related differences in GST activities for any of the substrates studied during fetal development. The Km values of GST for CDNB, PNB and EA were 1112, 1039 and 205 mumol/L, respectively. The conjugation of GST may play an important role in fetal hepatic metabolism of toxic electrophiles.