Carbohydrate metabolism carbon dioxide fixation

The dark reaction involves the fixation of carbon dioxide to form carbohydrates. The ATP and the NADPH produced in the light reaction drive this carbon fixation. It might be thought that the interruption of the Calvin cycle would also produce effective herbicides but this is not the case. There are two reasons why. First, the reaction is not an energetic reaction whose interruption would lead to the destruction of cellular components and second, the enzymes involved in the process are present in very high amounts. If an enzyme is to be targeted as a key step in the metabolism of a plant, it is important that it is present in small amounts and that it is not turned over very quickly. If an enzyme is abundant,... 

Recent work by Calvin and co-workers and by Horecker et al. have demonstrated the importance of sedoheptulose in the photosynthetic cycle of the carbohydrates as being a transitory intermediate in the regeneration of D-erythropentulose, the monosaccharide involved in the fixation of carbon dioxide . This sugar also plays a part in animal carbohydrate metabolism. Its most characteristic chemical property is its ready conversion into sedoheptulosan.(2,7-anhydro-j8-D-altroheptulopyranose (LVII). 

---