RuBisCo activase is present in the pyrenoid of green algae

Document Type

Article

Publication Date

2-1-1991

Publication Title

Protoplasma

Volume

162

Issue

1

First Page

38

Keywords

Green algae, Immunocytochemistry, Pyrenoid, RuBisCo, RuBisCo activase

Last Page

45

Abstract

RuBisCo activase catalyzes the activation and maintains the activated state of the photosynthetic enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCo, EC 4.1.1.39). We employed antisera prepared against the RuBisCo holoenzyme purified from tobacco and RuBisCo activase isolated from spinach to determine the localization of these proteins in leaves of C3-type higher plants and green algae. In leaves of Vicia faba, both RuBisCo activase and RuBisCo are distributed throughout the chloroplast stroma. In contrast, RuBisCo activase and RuBisCo are predominantly localized to the pyrenoid in the green algae Chlamydomonas reinhardtii and Coleochaete scutata. The co-immunolocalization of RuBisCo activase and RuBisCo to the pyrenoid in these two green algal species suggests that pyrenoid-localized RuBisCo is catalytically competent. We conclude that the pyrenoid functions as a unique metabolic compartment of the chloroplast in which the reactions of the photosynthetic carbon reduction pathway are initiated. © 1991 Springer-Verlag.

DOI

10.1007/BF01403899

ISSN

0033183X

E-ISSN

16156102

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