IDENTIFICATION AND LOCALIZATION OF THE FIRST GLUTAREDOXIN IN LEAVES OF A HIGHER-PLANT

Glutaredoxin(thioltransferase) has been identified and purified to hom ogeneity from spinach leaves. Its cytosolic localization was demonstra ted by chromatographic and immunological analysis of extracts from iso lated spinach chloroplasts and mitochondria, respectively. Spinach glu taredoxin shows a significant crossreactivity with antibodies raised a gainst E. coli glutaredoxin and possesses a specific thioltransferase activity comparable to that of the E. coli protein. Minor thioltransfe rase activities (less than 10% of total leaf activity) have been obser ved in spinach chloroplasts which are probably due to the presence of trypsin inhibitor and thioredoxins (TRf and TRm).