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BRENDA KEGG MetaCyc

photosynthesis (BRENDA)

:= BRENDA, := KEGG, := MetaCyc, := SABIO-RK
:= amino acid sequences := show the reaction diagram
EC Number
Reaction
Pathways
Reaction IDs
Stoichiometry Check
Missing Substrate
Missing Product
Commentary
Remark
7.1.1.6
plastoquinol-plastocyanin reductase
plastoquinol + 2 oxidized plastocyanin + 2 H+[side 1] = plastoquinone + 2 reduced plastocyanin + 4 H+[side 2]
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: The reaction catalyzed by EC-7.1.1.6 is achieved by the Q-cycle. The Q-cycle can be divided into two halves. In the first half, a molecule of Plastoquinols plastoquinol transfers its electrons via bifurcation to two acceptors: the first electron is transferred to Plastocyanin-Reduced, releasing a proton to the thylakoid lumen and forming a radical Semiplastoquinones semiplastoquinone. The semiquinone radical donates the second electron to cytochrome b6, where it is transferred to a different PLASTOQUINONE plastoquinone molecule, forming another semiplastoquinone radical. This sequence of events can be summarized by the following reaction: RXN-22952 In the second half of the cycle, another Plastoquinols plastoquinol is processed in a similar manner. It too transfers its electrons via bifurcation to Plastocyanin-Reduced, releasing a second proton to the thylakoid lumen and forming a radical Semiplastoquinones semiplastoquinone. This radical transfers the second electron to cytochrome b6. However, at this point the second cycle differs from the first one, since the second electron reaches the semiquinone that formed during the first half cycle, resulting in its reduction to Plastoquinols plastoquinolin a reaction that extracts two protons from the cytoplasmic side of the thylakoid membrane. This half cycle could be summarized as follows: TRANS-RXN-509
natural substrates, generic
glyceraldehyde-3-phosphate dehydrogenase (phosphorylating)
D-glyceraldehyde 3-phosphate + phosphate + NADP+ = 3-phospho-D-glyceroyl phosphate + NADPH + H+
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: NAD+ (ec 1.2.1.59, see R01061)
natural substrates
glyceraldehyde-3-phosphate dehydrogenase (NADP+) (phosphorylating)
D-glyceraldehyde 3-phosphate + phosphate + NADP+ = 3-phospho-D-glyceroyl phosphate + NADPH + H+
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: NAD+ (ec 1.2.1.59, see R01061)
natural substrates
glyceraldehyde-3-phosphate dehydrogenase (NAD(P)+) (phosphorylating)
D-glyceraldehyde 3-phosphate + phosphate + NADP+ = 3-phospho-D-glyceroyl phosphate + NADPH + H+
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: NAD+ (ec 1.2.1.59, see R01061)
natural substrates
glyceraldehyde-3-phosphate dehydrogenase (NADP+)
D-glyceraldehyde 3-phosphate + phosphate + NADP+ = 3-phospho-D-glyceroyl phosphate + NADPH + H+
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: NAD+ (ec 1.2.1.59, see R01061)
natural substrates
photosystem I
reduced plastocyanin + oxidized ferredoxin + hv = oxidized plastocyanin + reduced ferredoxin
generic compounds
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natural substrates, generic
ribulose-bisphosphate carboxylase
2 3-phospho-D-glycerate + 2 H+ = D-ribulose 1,5-bisphosphate + CO2 + H2O
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: multi-step reaction (isomerization, carboxylation, hydration and cleavage)
natural substrates, multi-step reaction
fructose-bisphosphate aldolase
sedoheptulose 1,7-bisphosphate = glycerone phosphate + D-erythrose 4-phosphate
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: This is an alternative substrate reaction of E.C. 4.1.2.13.
natural substrates