Fructose 1,6-bisphosphate

Fructose 1,6-phosphate is fructose sugar phosphorylated on carbons 1 and 6 (ie. is a fructosephosphate). The β- D -form of this compound is very common in cells. The vast majority of glucose and fructose entering a cell will become converted to fructose 1,6-phosphate at some point.

Fructose 1,6-phosphate in glycolysis
Fructose 1,6-phosphate lies within the glycolysis metabolic pathway and is produced by phosphorylation of fructose 6-phosphate. It is in turn broken down into two compounds; glyceraldehyde 3-phosphate and glycerone phosphate. It is allosteric activator of pyruvate kinase.

The numbering of the carbon atoms indicates the fate of the carbons according to their position in fructose 6-phosphate.

Fructose 1,6-phosphate isomerism
Fructose 1,6-phosphate has only one biologically active isomer, the β- D -form. There are many other isomers, analogous to those of fructose.