72
3 3
ted tridum from H-CTP at a ten fold greater rate than H-UTP. However,
3
about fifty percent of the incorporating activities from both H-CTP and
3 3
H-UTP are DNA dependent which is in contrast to the H-CTP incorporating
activities in renografin purified mitochondria which was not DNA dependent.
Solubilization of the Mitochondrial
RNA Polymerase Activity
The difficulty of defining proper conditions for solubilization of
the chloroplast RNA polymerase of Euglena gracilis (166,185) plus the
rapid inactivation of mitochondrial RNA polymerase activities by some
solubilization methods (11), prompted the investigation to determine
optimum conditions for solubilizing the activity from Euglena mitochon
dria (Table 10). An approach used by Rogall and Wintersherger (15) were
used to determine the optimum conditions for solubilization of the
mitochondrial RNA polymerase. A volume of mitochondrial suspension in
lysis buffer was added to an equal volume of the detergent-KCl solution
to bring the mixture to the indicated final concentrations. The mixtures
were centrifuged at 30,000 rpm to sediment non-solubilized material and
the supernatants were assayed for RNA polymerase activities. The
efficiencies of the different treatments in the solubilizations of RNA
polymerase activity from the mitochondria are summarized in Table 10.
It can be seen that the combined treatment with KC1 and Triton X-100
produced the highest yield of activity solubilized. However, NP-40, a
detergent employed by other investigators (15,173), and 0.5 M KC1 was
almost as effective. Treatment with 0.5 M KC1 alone failed to solubi
lize significant RNA polymerase activity. Treatment with either deter
gent alone was significantly less than with the Triton X-100 plus 0.5
M KC1 treatment which completely destroyed the succinic dehydrogenase