Calvin Cycle (carbon fixation stages)

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© IUBMB 2003

The net reaction when three molecules of ribulose 1,5-bisphosphate undergo this reaction is:

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

The cycle is completed by reconversion of 5 molecules of glyceraldehyde 3-phosphate into 3 molecules of ribulose bisphosphate and 2 of phosphate; click here for pathway of the rest of the Calvin cycle. The sixth molecule of glyceraldehyde phosphate represents net carbohydrate synthesis. The light reaction provides the NADPH and ATP that drive the overall biosynthesis.

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rest of Calvin cycle
EC 1.2.1.13 glyceraldehyde-3-phosphate dehydrogenase (NADP+) (phosphorylating)
EC 2.7.2.3 phosphoglycerate kinase
EC 4.1.1.39 ribulose-bisphosphate carboxylase