ribulose bisphosphate

Examples of ribulose bisphosphate in the following topics:

• The Calvin Cycle

  • In the stroma, in addition to CO2,two other components are present to initiate the light-independent reactions: an enzyme called ribulose bisphosphate carboxylase (RuBisCO) and three molecules of ribulose bisphosphate (RuBP).

• The Energy-Requiring Steps of Glycolysis

  • A second ATP molecule donates a high-energy phosphate to fructose-6-phosphate, producing fructose-1,6-bisphosphate.
  • The newly-added high-energy phosphates further destabilize fructose-1,6-bisphosphate.
  • The fourth step in glycolysis employs an enzyme, aldolase, to cleave 1,6-bisphosphate into two three-carbon isomers: dihydroxyacetone-phosphate and glyceraldehyde-3-phosphate.

• Control of Catabolic Pathways

  • The enzyme's activity is increased when fructose-1,6-bisphosphate levels increase.
  • (Recall that fructose-1,6-bisphosphate is an intermediate in the first half of glycolysis. ) The regulation of pyruvate kinase involves phosphorylation, resulting in a less-active enzyme.

• Methods of Intracellular Signaling

  • Enzymes known as kinases phosphorylate PI to form PI-phosphate (PIP) and PI-bisphosphate (PIP2).