Calvin Cycle

(regeneration of ribulose bisphosphate)

The carbon fixation part of the Calvin cycle (to see click here) showed how:

3 ribulose bisphosphate + 3 CO2 + 6 ATP + 6 NADPH + 3 H2O = 6 glyceraldehyde 3-phosphate + 6 NADP+ + 6 ADP + 6 phosphate

The stages below show how the cycle is completed by 5 molecules of glyceraldehyde phosphate being converted into 3 molecules of ribulose 5-phosphate and 2 molecules of phosphate. The scheme below shows how this can occur.

Thus the overall net reaction is:

3 CO2 + 9 ATP + 6 NADPH+ + 5 H2O = glyceraldehyde 3-phosphate + 6 NADP + 9 ADP + 8 phosphate

When cursor points to a box further details will be displayed in a tooltip window. If you click on the box you will change to appropriate enzyme specification.

© IUBMB 2003

The [C2] units are transferred from a ketose to an aldose by EC 2.2.1.1 transketolase. For structures see reaction scheme.

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enzymes homepage.
carbon fixation part of Calvin cycle
EC 2.2.1.1 transketolase (mechanism)
EC 2.7.1.19 phosphoribulokinase
EC 3.1.3.11 fructose-bisphosphatase
EC 3.1.3.37 sedoheptulose-bisphosphatase
EC 4.1.2.13 fructose-bisphosphate aldolase (mechanism)
EC 5.1.3.1 ribulose-phosphate 3-epimerase
EC 5.3.1.1 triose-phosphate isomerase
EC 5.3.1.6 ribose-5-phosphate isomerase