ISOLATION AND CHARACTERIZATION OF THE CLASS-ALPHA, CLASS-MU AND CLASS-PI GLUTATHIONE TRANSFERASES IN LLC-PK1 AND PIG-KIDNEY

Glutathione S-transferase (GST) isoenzymes from pig kidney cortex and LLC-PK1 (an established cell line derived from the pig proximal tubule ) were purified by affinity chromatography, anionic and cationic chrom atofocusing. Purification revealed nine isoenzymes in the pig kidney c ortex and five isoenzymes in the LLC-PK1 cell line. SDS-polyacrylamide gel electrophoresis showed that the pig kidney cortex isoenzymes were home- or heterodimeric; LLC-PK1 isoenzymes, however, were homodimeric . Isoenzymes from pig and LLC-PK1 showed a higher affinity towards glu tathione. The isoenzymes were further characterised and divided into t he different GST classes by studying specific inhibitors, specific sub strates and immunological properties. Pig GSTs belong to class alpha, mu and pi. The GSTs in LLC-PK1 cells, on the other hand, belong to cla ss pi and mu. The isoenzyme pattern in LLC-PK1 cells indicates the ded ifferentiation of this particular cell line compared with the pig kidn ey cortex.