含增生结节鼠肝谷胱甘肽转硫酶的纯化和性质研究

含增生结节鼠肝GST活性在纯化过程各步均较正常肝明显增高,经DEAE-52和CM-52柱层析分离得阴离子同工酶A-1和A-2以及阳离子同工酶C-1,C-2,C-3和C-4,用等电聚焦电泳测定等电点分别为6.7,6.3,7.4,7.9,8.3和8.6。SDS-PAGE结果显示,含增生结节肝GST在正常大鼠肝GSTYa,Yb和Yc区带相应的位置,出现3条区带,各亚基分子量分别为26,000,27,000和28,600道尔顿,但活性增高明显的C-3和C-4只出现1条相当于Yc亚基的区带。含增生结节肝GST6种同工酶的带电性质及亚基组成与正常肝无明显差别。阳离子同工酶C-3和C-4活性占上柱总活性的70%,说明含增生结节肝GST活性增高以阳离子同工酶为主。

PURFICATION AND PROPERTIES OF GLUTATHIONE-S-TRANSFERASE(GST)IN RAT LIVERS BEARING HYPERPLASTIC NODULES

The GST activity in the HN-bearing rat liver wasmarkedly increased at every step of purification as com-pared to that in the normal livers. Further purificationby CM-cellulose column and DEAE-cellulosecolumn chromatography resolved the GST into 4 distinctcationic isoenzymes designated C-1,C-2,C-3 andC-4,and 2 anionic isoenxymes designated A-1 andA-2, respectively. The pI values for iosenzymes onisoelectic locusing gels were 7.4,7.9,8.3,8.6,6.7 and 6.3,respectively. SDS-PAGE data on subunit compositionrevealed that GST in the HN-beating liver was com-posed of 3 subunits named Ya, Yb and Ye as in thenormal livers with Mr of 26,000, 27,500 and28,600,respectivety. but cationtic isoenzymes C-3 andC-4 showed a single band of Ye subunit No differ-ences in pI and subunit composition of GST isoenxymes between the HN-beating livers and the ???mal liverswere observed. C-3 and C-4 representedapproximateldy 70% of the total GST activity appliedonto the CM-52 column whereas A-1 andA-2 only 7%, indicating that canonic isoenzymesC-3 and C-4 aocount for most of the increased GSTacb?ity in the HN-heating livers.