title: Incorporation of phytol precursors into chlorophylls of tobacco cell cultures.
abstract: The incorporation of [1-(3)H] geranylgeranyl diphosphate (GGPP), [1-(3)H] geranylgeranyl monophosphate (GGMP) and [U-(14)C] phytyl diphosphate (PhPP) into chlorophylls a and b in growing tobacco cell cultures was investigated. The substrates were effectively incorporated into chlorophylls a and b, 3.2% of the total activity of applied GGPP or GGMP and 12.4% of the total activity of applied PhPP being found in chlorophylls a and b after 24 h incubation. The radioactivity was found in phytyl chlorophyllide through-out which means effective hydrogenation of the alcohol moiety in the case of GGPP and GGMP. With increasing substrate concentration, the specific radioactivity of chlorophyll increased up to a saturation level which was reached either at 20-40 μM PhPP or at 60 μM GGPP and GGMP. The specific radioactivity of the chlorophyll formed during the 24-h incubation period was the same as that of the applied substrate at saturating substrate concentration. The specific radioactivity of chlorophyll a was higher than that of chlorophyll b only in the case of PhPP.
authors.affiliation: Botanisches Institut der Universität, Menzinger Strasse 67, D-8000, München 19, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Benz
authors.forename: U
authors.initials: U
authors.lastname: Lempert
authors.forename: W
authors.initials: W
authors.lastname: Rüdiger