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Literature summary extracted from

  • Tongra, T.; Bharti, S.; Jajoo, A.
    Cyclic electron flow around photosystem I is enhanced at low pH (2014), Plant Physiol. Biochem., 83, 194-199 .
    View publication on PubMed

Activating Compound

EC Number Activating Compound Comment Organism Structure
1.97.1.12 additional information positive correlation between non-photochemical quenching (NPQ) and stimulation of CEF-PS I Spinacia oleracea

Localization

EC Number Localization Comment Organism GeneOntology No. Textmining
1.97.1.12 chloroplast
-
Spinacia oleracea 9507
-
1.97.1.12 thylakoid membrane
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Spinacia oleracea 42651
-

Natural Substrates/ Products (Substrates)

EC Number Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
1.97.1.12 reduced cytochrome b6 + oxidized ferredoxin + hv Spinacia oleracea
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oxidized cytochrome b6 + reduced ferredoxin
-
?

Organism

EC Number Organism UniProt Comment Textmining
1.97.1.12 Spinacia oleracea P80470 AND P06512 AND P10098 psaA, psaB, and psaC
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Source Tissue

EC Number Source Tissue Comment Organism Textmining
1.97.1.12 leaf
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Spinacia oleracea
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Substrates and Products (Substrate)

EC Number Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
1.97.1.12 reduced cytochrome b6 + oxidized ferredoxin + hv
-
Spinacia oleracea oxidized cytochrome b6 + reduced ferredoxin
-
?

Synonyms

EC Number Synonyms Comment Organism
1.97.1.12 PS I
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Spinacia oleracea

pH Range

EC Number pH Minimum pH Maximum Comment Organism
1.97.1.12 additional information
-
cyclic electron flow around photosystem I is enhanced at low pH of 5.5. The light response curve of PS I is significantly affected by acidification of the thylakoid membranes Spinacia oleracea

Cofactor

EC Number Cofactor Comment Organism Structure
1.97.1.12 plastoquinone
-
Spinacia oleracea

General Information

EC Number General Information Comment Organism
1.97.1.12 metabolism cyclic electron flow (CEF) can be stimulated to provide significant additional protection in plants when they are confronted with acidic pH conditions. But at low pH, the photosynthetic efficiency greatly decreases resulting in excessive excitation pressure in PS II and consequently an increased risk of damage on the donor side of PS II Spinacia oleracea
1.97.1.12 additional information cyclic electron flow around photosystem I is enhanced at low pH of 5.5. The light response curve of PS I is significantly affected by acidification of the thylakoid membranes Spinacia oleracea
1.97.1.12 physiological function cyclic electron flow (CEF) PS I is a highly dynamic, regulated and large capacity pathway involving ferredoxin (Fd) and Cytb6f complex. In CEF, the plastoquinone (PQ) pool is reduced by Fd which is photoreduced by PS I. The reduced PQ pool is oxidized by the Cytb6f complex, where DpH is generated across thylakoid membranes through the Q cycle. This DpH drives ATP synthase and produces the ATP required for the net CO2 assimilation and also stimulates NPQ. It has been proposed that there are two physiological functions of CEF in thylakoid membrane. During photosynthesis, cyclic electron flow around PSI can generate a pH gradient across the thylakoid membrane that not only is used to synthesize ATP, but can also induce thermal dissipation and provide protection for the photosynthetic apparatus Spinacia oleracea