Mitochondrial oxidase systems in neurospora
<p>Mitochondrial oxidase systems of Neurospora crassa were investigated with respect to their mechanisms of electron transport and their relationships to respiratory metabolism.</p> <p>A mitochondrial oxidase system able to utilize dihydroorotic acid as a primary substrate wa...
| Summary: | <p>Mitochondrial oxidase systems of Neurospora crassa were investigated
with respect to their mechanisms of electron transport and their
relationships to respiratory metabolism.</p>
<p>A mitochondrial oxidase system able to utilize dihydroorotic acid
as a primary substrate was found and characterized. Another substrate
for this system was isolated from yeast extract and identified as 5-N-methylformamido-L-dihydroorotic acid. This system was found to occur
in both wildtype and poky, a respiratory mutant. No linkage to the
cytochrome chain or to oxidative phosphorylation could be detected.</p>
<p>A succinate oxidase system and NADH oxidase system independent of
cytochromes b,a, and a<sub>3</sub> were found to occur in both wildtype and in
the poky mutant. The system was partially characterized using the
poky mutant, which is deficient in cytochromes b,a and a<sub>3</sub>.
It was found that this oxidase system was a part of respiratory metabolism and
was linked to oxidative phosphorylation.</p>
<p>Mechanisms of electron transport in these oxidase systems are discussed
and models presented.</p>
<p>Possible biological origins and the biological significance of
5 N-methylformamidodihydroorotic acid are also discussed.</p>
<p>The development of poky and wildtype mitochondria during the growth
cycle were studied and compared. Differences in morphology were detected
using electron microscopy and differences in cytochrome content were
detected by absorption spectroscopy. The relationships between the oxidase
systems and mitochondrial development are discussed.</p>
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