BREAKDOWN OF CHLOROPHYLLS BY SOLUBLE-PROTEINS EXTRACTED FROM LEAVES OF CHENOPODIUM-ALBUM

Chlorophylls were degraded by soluble proteins extracted from leaves o f Chenopodium album. The bleaching (oxidative cleavage) of chlorophyll s and accumulation of pheophorbides were observed. The accumulation of pheophorbides was not inhibited by anoxygenic conditions or by ascorb ate, but the bleaching of chlorophylls was inhibited. It appears that there are two distinct degradation pathways: chlorophyll bleaching and pheophorbide accumulation in the process of chlorophyll breakdown. Th e bleaching reaction was not. affected by hydrogen peroxide or hydroge n peroxide and 2,6-dichloroindophenol, but was slightly inhibited by l inolenic acid. Catalase had no effect, but superoxide dismutase inhibi ted weakly. This bleaching was strongly inhibited by tiron and ascorba te. These results suggest that active oxygen, probably the superoxide radical, may be involved, but the enzymes catalase, peroxidase, and li poxidase are not responsible for the bleaching reaction. The accumulat ion of pheophorbide derivatives is discussed in relation to the inhibi tion of bleaching activity.