Pyropheophytin a Accompanies Pheophytin a in Darkened Light Grown Cells of Euglena1

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Abstract
Chromatography Light-grown non-dividing cells of Euglena gracilis Klebs var. bacillaris Cori form pheophytin a like pigments from chlorophyll a without loss of viability when they are allowed to incubate in darkness without shaking. This is accompanied by the loss of long-wavelength components in the red absorption band of intact cells. After extraction of these cells with acetone, transfer of the pigments to ether and treatment of the ether solution with dilute acid, two pigments can be separated by high performance liquid chromatography on reverse phase silica gel (RP-8) using methanol: water = 95:5 (v/v) as the eluting solvent: In addition to pheophytin a, the eluate contains an unknown pigment. With increasing times of incubation of the cells in darkness, the proportion of pheophytin a decreases and the proportion of the unknown increases suggesting, that the unknown is formed from pheophytin a. This pigment has been identified as pyropheophytin a. It has the same absorption spectrum as pyropheophytin a (prepared by pyridine pyrolysis of pheophytin a) and contains phytol as the longchain esterifying alcohol. On conversion to the methyl ester, the resulting methyl phorbide is identical with authentic pyromethylpheophorbide a by tic, hplc, absorption, absorption difference and mass spectros­ copy. This is the first report of pyropheophytin a or any pyrochlorophyll derivative from plants or oxygenic plant-like microorganisms where it may serve as an intermediate in chlorophyll degradation.

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