Send to:

Choose Destination
See comment in PubMed Commons below
Proc Natl Acad Sci U S A. 1993 Jun 15;90(12):5514-8.

Calvin cycle multienzyme complexes are bound to chloroplast thylakoid membranes of higher plants in situ.

Author information

  • 1Institute of Plant Genetics and Crop Plant Research, Gatersleben, Federal Republic of Germany.


Further evidence is provided that the Calvin cycle enzymes ribose-5-phosphate isomerase (EC, ribulose-5-phosphate kinase (Ru-5-P-K, EC, ribulose-1,5-bisphosphate carboxylase (RuP2Case, EC, glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC, sedoheptulose-1,7-bisphosphatase (Sed-1,7-bPase, EC, and electron transport protein ferredoxin-NADP+ reductase (FNR, EC are organized into stable CO2-fixing multienzyme complexes with a molecular mass of 900 kDa. Limited trypsinolysis combined with immunoblotting revealed that all of chloroplast stromal Ru-5-P-K and GAPDH is located in enzyme complexes. The Calvin cycle enzyme complexes remain intact indefinitely at lower ionic strength but dissociate into components at KCl concentrations >250 mM. Immunoelectron microscopy showed that Ru-5-P-K, GAPDH, Sed-1,7-bPase, and FNR are bound to stroma-faced thylakoid membranes in situ, whereas RuP2Case and RuP2Case activase are randomly distributed throughout chloroplasts. The results indicate that membrane-bound enzyme supercomplexes may play an important role in photosynthesis.

Free PMC Article
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk