GLUTATHIONE TRANSFERASE ISOENZYMES IN OLFACTORY AND RESPIRATORY EPITHELIUM OF CATTLE

Glutathione transferase (GST) was investigated in the olfactory and re spiratory epithelium of cattle. A significantly more abundant GST in t erms of either protein amount or activity was found in the olfactory r ather than in the respiratory epithelium. No apparent qualitative diff erences in the isoelectric focusing, sodium dodecyl sulphate-polyacryl amide gel electrophoresis (SDS-PAGE) and HPLC profiles were noted in t he reduced glutathione (GSH) affinity purified GST pool of olfactory a nd respiratory epithelium. Both tissues have at least six GST isoenzym es with isoelectric point values of 4.9 (peak I), 5.3 (peak II), 5.95 (peak III), 6.5 (peak IV), 7.1 (peak V) and 9.3 (peak VI). From both t issues at least seven different GST subunits can be resolved by HPLC a nalysis. The GST isoenzymes having pI at 5.3 and 9.3 were predominantl y expressed in the olfactory than in the respiratory epithelium. These latter forms conjugate GSH efficiently with alkenals and hydroperoxid es, respectively. Kinetic, immunological and structural properties, in cluding HPLC analysis and N-terminal region amino acid sequence seem t o indicate that the bovine nasal mucosa tissue in addition to a GST su bunit which is orthologue to rat subunit 8 (alpha class) express tissu es specific subunits.