Localization of p110 protein, TUTase activity and GDH activity in glycerol gradient fractions of mitochondrial TS extract. A. Aliquots (25 and 15 ml) of each gradient fraction were assayed for TUTase and GDH activities, respectively. B. Aliquots (3 ml) of each gradient fraction were electrophoresed on SDS-acrylamide; the gel was blotted and the filter probed with p110 antiserum. Only fractions 1-9 are shown due to the absence of detectable bands in the remaining fractions. The superimposed graph shows the densitometric values of the bands. The gRNA-independent U-insertion activity sedimented in fractions 8-10 at approximately 20S (data not shown).