Ribulose 5-phosphate

Ribulose 5-phosphate is one of the end-products of the pentose phosphate pathway. It is also an intermediate in the Calvin cycle.

It is formed by phosphogluconate dehydrogenase in the pentose phosphate pathway. Ribulose 5-phosphate is involved in various metabolic pathways. Ribulose 5-phosphate can be acted upon by phosphopentose isomerase to form Ribose 5-phosphate, which is a precursor for nucleotide and co-factor biosynthesis. Ribulose-5 phosphate can also be acted upon by phosphopentose epimerase to form Xylulose 5-phosphate, which is used in the nonoxidative phase of the pentose phosphate pathway in humans to generate precursor molecules for the synthesis of aromatic amino acids and production of energy.

In plants, Ribulose 5-phosphate produced from the pentose-phosphate pathway is converted into Ribulose-1-5-bisphosphate by the enzyme phosphoribokinase.