Protochlorophyllide b does not occur in barley etioplasts

FEBS Letters

Rüdiger, Wolfhart¹  Scheumann, Verena¹  Oster, Ulrike¹  Helfrich, Michael¹  Klement, Harald¹  Schoch, Siegrid¹ 

[1] Botanisches Institut der Ludwig-Maximilians-Universität München, Menzingerstr. 67, 80638 München, Germany

关键词: Chlorophyll biosynthesis;    Chlorophyllid b;    Etiolated;    NADPH-protochlorophyllide oxidoreductase (POR);    Photoconversion;    Hordeum;    Chl;    chlorophyll;    Chlide;    chlorophyllide;    DDQ;    2;    3-dichloro-5;    6-dicyano-benzoquinone;    Pchl;    protochlorophyll;    Pchlide;    protochlorophyllide;    Ppheide;    protopheophorbide;    POR;    NADPH:protochlorophyllide oxidoreductase;   

DOI  :  10.1016/S0014-5793(99)00169-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Barley (Hordeum vulgare L.) etioplasts were isolated, and the pigments were extracted with acetone. The extract was analyzed by HPLC. Only protochlorophyllide a and no protochlorophyllide b was detected (limit of detection <1% of protochlorophyllide a). Protochlorophyllide b was synthesized starting from chlorophyll b and incubated with etioplast membranes and NADPH. In the light, photoconversion to chlorophyllide b was observed, apparently catalyzed by NADPH:protochlorophyllide oxidoreductase. In darkness, reduction of the analogue zinc protopheophorbide b to zinc 7¹-hydroxy-protopheophorbide a was observed, apparently catalyzed by chlorophyll b reductase. We conclude that protochlorophyllide b does not occur in detectable amounts in etioplasts, and even traces of it as the free pigment are metabolically unstable. Thus the direct experimental evidence contradicts the idea by Reinbothe et al. (Nature 397 (1999) 80–84) of a protochlorophyllide b-containing light-harvesting complex in barley etioplasts.

【 授权许可】

Unknown