Ribulose biphosphate

Van den Broek, G., Timko, M.P., Kausch, A.P., Cashmore, A.R., Van Montagu, M. Herrera-Estrella, L. (1985). Targeting of a foreign protein to chloroplasts by fusion to the transit peptide from the small subunit of ribulose 1,5-biphosphate carboxylase. Nature, 313, 358-63. 

The light independent reactions take place in the stroma with the help of ATP and NADPH. In a process called the Calvin-Benson cycle, or carbon fixation, carbon dioxide from the atmosphere is captured and converted into carbohydrates [135]. The reaction is catalyzed by the enzyme RuBisCO (ribulose-1,5-biphosphate... 

A ribulose-1,5 -biphosphate carboxylase/oxygenase Mg2+ formation of an enediol(ate) addition of either C02 or 02/C-C bond cleavage... 

The general validity of these relationships has also been demonstrated with -lactoglobulin (21), ribulose 1,5-biphosphate carboxylase ( ), and soy glycinin (27). 

In the case of the major cytoplasmic protein of leaves, ribulose 1,5-biphosphate carboxylase (RUBISCO), the surface rheological properties and foam stability were maximum at pH 5.5, close to the isoelectric point (pH 4.8) and all parameters measured were greater than any other protein studied (2 ). This may be related to the large molecular size of RUBISCO, i.e. 560 000 daltons, and its disulfide stabilized globular structure. 

Martin, J. S. and M. M. Martin, Taimin assays in ecological studies. Precipitation of ribulose-1,5-biphosphate carboxylase/ oxygenase by tannic acid, quebracho, and oak foliage extracts, J. Chem. Ecol., 9, 285-294 (1983). 

H2CO is an abbreviation for a carbohydrate. The reaction is a part of the Calvin cycle. The enzyme necessary to carry out the binding of CO2 is called ribulose-1,5-biphosphate carboxylase oxygenase (RuBisCO). The mechanisms are not fully known. The cofactor ribulose-1,5-biphosphate, a rather small sugar phosphate molecule, binds to CO2 after abstraction of a proton. A covalent bond is formed between RuBis and CO2 (Figure 15.12). 

Scheme 9.165. A portion of the Calvin cycle showing the use of carbon dioxide in the enzyme-catalyzed reaction with ribulose-1,5-biphosphate.

A-Substituted carbamic acids or their anions play a key role as intermediates in several biological processes (carboxylations by biotin enzymes photosynthetic activation of CO2 promoted by Rubisco (ribulose 1,5-biphosphate carboxylase) glucuronidation, etc.) [10, 11, 31, 32]. 

Carbon dioxide combines with ribulose 1,5-biphosphate catalysed by an enzyme called rubisco, to produce two molecules of 3-phosphoglycerate (3-PGA)... 

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