Light-regulated pigment interconversion in pheophytin/chlorophyll-containing complexes formed during plant leaves greening

Upon illumination of etiolated maize leaves the photoconversion of protochlorophyllide Pchlide 655/650 into chlorophyllide Chlide 684/676 was observed. It was shown that chlorophyllide Chlide 684/676 in the dark is transformed into pheophytin Pheo 679/675 and chlorophyll Chi 671/668 by means of two parallel reactions, occurring at room temperature: Chlide 684/676 [GRAPHICS] The formed pheophytin Pheo 679/675 was unstable and in the dark was transformed into chlorophyll Chi 671/668 in a few seconds: Pheo 679/675 --> Chi 671/668. The last reaction is reversed by the light: Chl/668 -->(h nu) Pheo 679/675. Thus, on the whole in the greening etiolated leaves this process occurs according to the following scheme: [GRAPHICS] The observed light-regulated interconversion of Mg-containing and Mg-free chlorophyll analogs is activated by ATP and inhibited by AMP.