ACTION SPECTRA FOR INVIVO AND INVITRO CONVERSIONS OF PHYCOCHROME B, A REVERSIBLY PHOTOCHROMIC PIGMENT IN A BLUE-GREEN-ALGA, AND ITS SEPARATION FROM OTHER PIGMENTS

Phycochrome b, one of the reversibly photochromic pigments found in Tolypothrix distorta seems to exist in only two forms: Pb500 and Pb570. The pigment has been spectroscopically demonstrated in vivo. It has also been separated from other pigments. Two different methods for separation have been used: isoelectric focusing and gel filtration. Preparations of purified phycobilisomes contain phycochrome b. The in vivo and in vitro absorption difference spectra were determined as well as action spectra for the conversions in vitro and in vivo of Pb500 to Pb570 and vice versa. Transformation kinetics of phycochrome b show that the conversions in both directions are initially first‐order reactions. Copyright © 1979, Wiley Blackwell. All rights reserved