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Source of reducing equivalents for the in vitro synthesis of chlorophyll from protochlorophyll
Author(s) -
Griffiths W.T.
Publication year - 1974
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(74)80392-3
Subject(s) - citation , in vitro , library science , chemistry , stereochemistry , computer science , biochemistry
The terminal reactions of chlorophyll(ide) synthesis in higher plants involve the photoreduction of protein bound protochlorophyll(ide) by an unidentified hydrogen donor. Etiolated leaves of angiosperms accumulate both photoconvertible and non-photoconvertible PChl* species which can be identified by their absorption maxima in vivo in the red region of the spectrum [ 1 ] . The major phototransformable form is Pes2 the F’Chl holochrome. A second phototransformable species P637, occurs to a lesser extent in etiolated leaves. Non-phototransformable P630 varies in amount in different species and with age of plant but its level increases with 6-aminolevulinic acid (ALA) feeding [2]. Various explanations have been suggested to acount for the existence of the different forms of PChl ranging from whether the molecule exists free or bound to protefn [3], whether it is phytylated or not [4] or whether aggregation occurs to give monomeric or dimeric PChl complexes [5,6]. Further, attempts to physically separate the different absorbing forms have also been made [7-91. The studies reported here provide evidence suggesting NADPH as the hydrogen donor for PChl photoreduction. Again, some suggestions regarding the relationship between non-photoconvertible Psso and photoconvertible P652 can also be offered from the results of this study.