Chlorophyll a formation in the chlorophyll b reductase reaction requires reduced ferredoxin

Citation
V. Scheumann et al., Chlorophyll a formation in the chlorophyll b reductase reaction requires reduced ferredoxin, J BIOL CHEM, 273(52), 1998, pp. 35102-35108
Citations number
43
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biochemistry & Biophysics
Journal title
JOURNAL OF BIOLOGICAL CHEMISTRY
ISSN journal
0021-9258 → ACNP
Volume
273
Issue
52
Year of publication
1998
Pages
35102 - 35108
Database
ISI
SICI code
0021-9258(199812)273:52<35102:CAFITC>2.0.ZU;2-Z
Abstract
The reduction of chlorophyllide b and its analogue zinc pheophorbide b in e tioplasts of barley (Hordeum vulgare L.) was investigated in detail. In int act etioplasts, the reduction proceeds to chlorophyllide a and zinc pheopho rbide a or, if incubated together with phytyldiphosphate, to chlorophyll a and zinc pheophytin a, respectively. In lysed etioplasts supplied with NADP H, the reduction stops at the intermediate step of 7(1)-OH-chlorophyll(ide) and Zn-7(1)-OH-pheophorbide or Zn-7(1)OH-pheophytin. However, the final re duction is achieved when reduced ferredoxin is added to the lysed etioplast s, suggesting that ferredoxin is the natural cofactor for reduction of chlo rophyll b to chlorophyll a. The reduction to chlorophyll a requires ATP in intact etioplasts but not in lysed etioplasts when reduced ferredoxin is su pplied. The role of ATP and the significance of two cofactors for the two s teps of reduction are discussed.