Derivation of the formyl‐group oxygen of chlorophyll b from molecular oxygen in greening leaves of a higher plant (Zea mays)

FEBS Letters

Cmiel, E.¹  Schäfer, W.³  Katheder, Ingrid²  Scheer, H.²  Porra, R.J.² 

[1] Institut für Physikalische Chemie, Technische Universität München, W-8046 Garching, Germany;Botanisches Institut der Universität, W-8000 München 19, Germany;Max-Planck-Institut für Biochemie, W-8033 Martinsried, Germany

关键词: Biosynthesis;    Photosynthesis;    Chlorophyll b;    18Oxygen;    Isotope exchange;    Reductive extraction;    Oxygenase;    Chl;    chlorophyll;    DCMU;    3-(3;    4-dichlorophenyl)-1;    1- dimethylurea;    DEAE-cellulose;    diethylaminoethyl-cellulose;    FAB;    fast-atom-bombardment;    Phe;    phaeophytin. The IUB-IUPAC approved numbering system for tetrapyrroles has been used with bracket [] nomenclature for substitutions. [7-hydroxymethyl]-Chl b is identical to [7-hydroxymethyl]-Chl a but will be referred to here as a Chl b derivative to indicate its origin;   

DOI  :  10.1016/0014-5793(93)81442-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Using mass spectroscopy, we demonstrate as much as 93% enrichment of the 7-formyl group oxygen of chlorophyll b when dark-grown, etiolated maize leaves are greened under white light in the presence of ¹⁸O₂. This suggests that a mono-oxygenase is involved in the oxidation of its methyl group precursor. The concomitant enrichment of about 75% of the 13¹-oxygen confirms the well-documented finding that this oxo group, in both chlorophyll a and b, also arises from O₂. High ¹⁸O enrichment into the 7-formyl oxygen relative to the substrate ¹⁸O₂ was achieved by optimization of the greening conditions in combination with a reductive extraction procedure. It indicates not only a single pathway for Chl b formyl group formation, but also unequivocally demonstrates that molecular oxygen is the sole precursor of the 7-formyl oxygen.

【 授权许可】

Unknown