RRC ID 4821
著者 Schelbert S, Aubry S, Burla B, Agne B, Kessler F, Krupinska K, Hörtensteiner S.
タイトル Pheophytin pheophorbide hydrolase (pheophytinase) is involved in chlorophyll breakdown during leaf senescence in Arabidopsis.
ジャーナル Plant Cell
Abstract During leaf senescence, chlorophyll is removed from thylakoid membranes and converted in a multistep pathway to colorless breakdown products that are stored in vacuoles. Dephytylation, an early step of this pathway, increases water solubility of the breakdown products. It is widely accepted that chlorophyll is converted into pheophorbide via chlorophyllide. However, chlorophyllase, which converts chlorophyll to chlorophyllide, was found not to be essential for dephytylation in Arabidopsis thaliana. Here, we identify pheophytinase (PPH), a chloroplast-located and senescence-induced hydrolase widely distributed in algae and land plants. In vitro, Arabidopsis PPH specifically dephytylates the Mg-free chlorophyll pigment, pheophytin (phein), yielding pheophorbide. An Arabidopsis mutant deficient in PPH (pph-1) is unable to degrade chlorophyll during senescence and therefore exhibits a stay-green phenotype. Furthermore, pph-1 accumulates phein during senescence. Therefore, PPH is an important component of the chlorophyll breakdown machinery of senescent leaves, and we propose that the sequence of early chlorophyll catabolic reactions be revised. Removal of Mg most likely precedes dephytylation, resulting in the following order of early breakdown intermediates: chlorophyll --> pheophytin --> pheophorbide. Chlorophyllide, the last precursor of chlorophyll biosynthesis, is most likely not an intermediate of breakdown. Thus, chlorophyll anabolic and catabolic reactions are metabolically separated.
巻・号 21(3)
ページ 767-85
公開日 2009-3-1
DOI 10.1105/tpc.108.064089
PII tpc.108.064089
PMID 19304936
PMC PMC2671698
MeSH Amino Acid Sequence Arabidopsis* / anatomy & histology Arabidopsis* / physiology Arabidopsis Proteins / classification Arabidopsis Proteins / genetics Arabidopsis Proteins / metabolism* Cellular Senescence / physiology* Chlorophyll / metabolism* Chloroplasts / enzymology Hydrolases / classification Hydrolases / genetics Hydrolases / metabolism* Membrane Proteins / genetics Membrane Proteins / metabolism Molecular Sequence Data Mutation Phenotype Pheophytins / genetics Pheophytins / metabolism* Photosynthesis / physiology Phylogeny Phytol / metabolism Plant Leaves / cytology Plant Leaves / physiology* Recombinant Fusion Proteins / genetics Recombinant Fusion Proteins / metabolism Sequence Alignment
IF 9.618
引用数 309
WOS 分野 PLANT SCIENCES BIOCHEMISTRY & MOLECULAR BIOLOGY CELL BIOLOGY
リソース情報
シロイヌナズナ / 植物培養細胞・遺伝子 pda03231