Oxygen and Light Induced Oxidations of Cytochrome, Flavoprotein, and Pyridine Nucleotide in a Chlamydomonas Mutant.

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Abstract
Utilizing sensitive spectrophotometric techniques and a pale green mutant of Chlamydomonas which carries out an active photosynthesis with a low chlorophyll content, the components of the respiratory chain have been investigated. It is found that pyridine nucleotide, flavoprotein and cytochromes b and c are present in amounts typical of other microorganisms. The terminal oxidase is present in such a low concentration relative to the other cytochromes that it has not been surely identified. Pyridine nucleotide is affected by light aerobically and anaerobically; flavoprotein is scarcely changed under either condition. Cytochrome b responds most sensitively to illumination anaerobically but responds very little to illumination aerobically. Cytochrome f responds rapidly to illumination under aerobic conditions, and sluggishly under anaerobic conditions. No evidence of increased absorption at 518 mu upon illumination is recorded. Since the mutant has a high photosynthetic activity per unit chlorophyll content, it is probable that the compound absorbing at 518 mu and observed upon illumination of the normal cells is not an essential intermediate in photosynthesis.
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