title: Removal of magnesium by Mg-dechelatase is a major step in the chlorophyll-degrading pathway in Ginkgo biloba in the process of autumnal tints.
abstract: Autumnal tints are one of the most manifest and fascinating natural phenomena, but the mechanism of chlorophyll (Chl)-breakdown in deciduous trees has not been fully elucidated. In this study, we analyzed the composition of Chl-related compounds and determined the activities of initial Chl-degrading enzymes in Ginkgo leaves at various stages in the process of autumnal coloring. Only pheophytin a (Pheo a, Mg-free Chl a) was detected in yellow leaves by HPLC analysis, and the activity of Mg-dechelatase in yellow leaves was found to be higher than in green leaves. These findings showed that the removal of magnesium from Chl a occurred in advance of dephytylation in the Ginkgo.
authors.affiliation: Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Japan.
authors.forename: L
authors.initials: L
authors.lastname: Tang
authors.forename: A
authors.initials: A
authors.lastname: Okazawa
authors.forename: E
authors.initials: E
authors.lastname: Fukusaki
authors.forename: A
authors.initials: A
authors.lastname: Kobayashi
mesh_terms: D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002734:Chlorophyll / Q000032:analysis / Q000378:metabolism*; D000077194:Chlorophyll A; D004798:Enzymes; D020441:Ginkgo biloba / Q000201:enzymology / Q000502:physiology*; D010674:Pheophytins / Q000032:analysis; D018515:Plant Leaves / Q000201:enzymology; D010946:Plants, Medicinal; D012621:Seasons
chemical_list: D002352:Carrier Proteins; D004798:Enzymes; D010674:Pheophytins; C421174:magnesium dechelatase; D002734:Chlorophyll; C061694:pheophytin a; D000077194:Chlorophyll A