Structure of rubisco
Rubisco is found in the chloroplasts and is the most abundant protein in the plant biomass, and even in the total biomass.
It generally consists of two types of protein subunits coded for by two different genes, large (L for large) and smaller (S for small) each type of complete rubisco having eight subunits. The active sites are generally located on the large subunits.
Function of rubisco
- a carboxylase activity through which rubisco binds a CO2 onto D-ribulose-1.5-diphosphate to form two molecules as 3-phospho-D-glycerate;
- an oxygenase activity through which rubisco binds a molecule of O2 onto D-ribulose-1.5-diphosphate to form 3-phospho-D-glycerate and 2-phosphoglycolate.
Rubisco therefore plays an active role in the carbon cycle.
Plan of the Calvin cycle. © Mike Jones, Wikimedia CC by-sa 3.0