Highly purified samples of phytochrome from etiolated oat (Avena sativa L.) seedlings were analyzed for sugar content. Phytochrome was found to be a glycoprotein, with about 4% of its weight as carbohydrate. In addition, modifications in the procedure for purifying phytochrome are proposed here and certain details about the protocol are discussed that improve the yield and reproducibility of previously published methods.S. J. ROUX, S. G. LISANSKY AND B. M. STOKER Physiol. Plant. 35.1975

No abstract

After electrophoresis on sodium dodecyl sulfate polyacrylamide gels, bleached chromopeptides of phytochrome can have their blue color restored by soaking the gels in 20% trichloroacetic acid. The blue bands have a broad absorption maximum between 630 and 655 nm, characteristic of denatured phytochrome. The restored color retains most of its intensity for up to 2 h, but gradually bleaches again until it disappears completely within 24 h. This visualization method is used to identify the number and sizes of phytochrome chromopeptides produced by limited tryptic digestion. The results reveal some structural requirements for photoreversibility and are consistent with a model of phytochrome structure that predicts a high degree of symmetry within the native subunit.