Isolation of the Red-light-absorbing Form of Phytochrome from Light-grown Pea Shoots

Abstract

Phytochrome was extracted from both light-grown and dark-grown shoots of Pisum and partially purified by brushite chromatography and ammonium sulfate fractionation. About 160–270 ng of phytochrome per g green tissue extracted was recovered after the partial purification while about 5.1–8.6 μg of phytochrome per g etiolated tissue was recovered. Only the red-light-absorbing form of phytochrome was detected in extracts prepared from both light- and dark-grown tissue, even though the light-grown tissue was harvested in daylight and purification was done entirely at 0–4°C with only a dim green safe light. No significant differences were found between phytochrome purified from green and etiolated tissues, either in their spectral properties or in their immunochemical reactivity against antietiolated-zucchini-phytochrome serum.