Production and purification of polyclonal antibodies to Pisum and Avena labile phytochrome which cross-react with phyA from Pharbitis nil

Little work was done so far with phytochrome from Pharbitis nil. Purificati on of phyA from this plant has been exceptionally difficult. Labile phytoch rome was presented in too small amount to obtain either absorption spectra or enough protein to produce antibodies. Monoclonal antibodies mAP5, MAC 50 , 52, 198 recognized Pharbitis nil labile phytochrome poorly, so it was nec essary to develop independently an antiserum against labile phytochrome. Th e antiserum was prepared against proteolytically undegraded phytochrome obt ained from etiolated Avena and Pisum seedlings using conventional methods. The antiserum to phytochrome from each of the above mentioned plants was pr epared by injecting purified phytochrome into rabbits. The newly produced p olyclonal antibodies to phyA from Avena and Pisum were used to characterize phytochrome from etiolated seedlings of Pharbitis nil. The cross reaction was tested by immunobloting. Both kinds of PAbs recognised phyA from Pharbi tis nil, however IgG against the labile phytochrome from Pisum gave stronge r reaction. The recognized peptide had the molecular weight of about 120-kD a.