PURIFICATION AND CHARACTERIZATION OF P-52 (GLUTATHIONE S-TRANSFERASE-P OR S-TRANSFERASE-7-7) FROM NORMAL LIVER AND PUTATIVE PRENEOPLASTIC LIVER NODULES

  • 15 May 1988
    • journal article
    • research article
    • Vol. 48  (10) , 2805-2812
Abstract
A previously study from our laboratory (L. C. Eriksson et al., Biochem. Biophys. Res. Commun., 117:740-745, 1983) revealed that a cytosolic polypeptide of approximate Mr 21,000 (designated P-21) was markedly elevated in amount in hepatocyte nodules induced by six different regimens. The molecular weight of this polypeptide, subsequently revised to approximately 26,000, was redesignated P-26 and was identified (T. H. Rushmore et al., Biochem. Biophys. Res. Commun., 143:98-103, 1987) as a subunit of a placental form of glutathione S-transferase (K. Sato et al, Gam 75: 199-202, 1984), also named glutathione S-transferase 7-7 (H. Jensson et al., FEBS Lett., 187: 115-120, 1985). The describe here a convenient method for purifying relatively large amounts of P-26 from hepatocyte nodules involving the sequential use of affinity chromatography on S-hexyl glutathione-Sepharose 4B, CM-Sephadex, and DEAE-Sephacel. Evidence is presented that P-26 exists as a dimer of approximate Mr 52,000 (P-52). Analyses by two-dimensional electrophoresis have indicated that the subunits of Mr 26,000 may consist of five separate charged isomers. Investigations using appropriate antisera and analysis by amino acid sequencing have provided additional confirmation that P-452 is probably identical to rat placental glutathione S-transferase. Antibodies to P-52 are proving to be useful as a marker of new cell populations that appear regularly during hepatocarcinogenesis.