85
Enzymatic Properties of the
Mitochondrial RNA Polymerase
The dependence of the mitochondrial RNA polymerase on the concen
tration of MnC^ is shown in Figure 13. Low concentration (about 1 mM)
j |
of Mn stimulated the activity of this enzyme and higher concentrations
decreased the activity. However, the enzyme activities were also stimu-
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lated by low concentrations of Mg (Figure 14) demonstrating the optimal
concentration at 0.5 mM.
The template requirement of the mitochondrial enzyme is summarized
in Table 16. The mitochondrial enzyme prefers poly d(AT) as a template
which is similar to the rifampicin sensitive mitochondrial RNA polymerase
from Neurospora crassa, described by Kuntzel and Schafer (11). It is
interesting to note that while Euglena nuclear DNA was a more effective
template than denatured calf thymus DNA that it is not necessarily a
more preferred template than Euglena mitochondrial DNA. The mitochondrial
DNA was only available in 1/5 the saturating DNA concentration and a
comparison of the templates was not possible.