Reductive Pentose Pathway

Reductive Pentose Pathway

	Reductive Pentose Pathway - It utilizing the ribulose dipliosphate carboxylase reaction, is also found in CO₂ fixation of higher green plants. The essential features of this pathway are as follows : (1) Ribulose monophosphate (RumP) is phosphorylated to ribulose 5-diphosphate (RudP) by the ATP-ADP reaction.
(2) CO₂ is used to carboxylate RudP through an unstable 6C intermediate and two molecules of 3-phosphoglyceric acid (PGA) are formed. (3) PGA is reduced through a two step process requiring ATP and NADPH to 3-phosphoglyceraldehyde (PGAL). PGAL is converted to its triose phosphate isomer dihydroxyacetone phosphate (DHAP).
(4) PGAL condenses with DHAP to form fructose-I-6-diphosphate which then forms fructole-6-phosphate. This hexose phosphate through a series of interconversions, regnerates RumP which is re used for CO₂.