[5] In the Pentose Phosphate Pathway, a transaldolase removes the first 3 carbon molecules of sedoheptulose 7-phosphate and places them onto a glyceraldehyde 3-phosphate.
A tetrose diphosphate molecule, D-threose 2,4-diphosphate, was discovered to be an inhibitor of glyceraldehyde 3-phosphate dehydrogenase.
[6] This tetrose diphosphate molecule inhibits the G3P dehydrogenase from performing catalysis because it oxidizes the enzyme by binding to it at the active site.
High concentrations of tetrose diphosphate must be used to outcompete the substrate, G3P, and block the function of G3P dehydrogenase.
[8] Phosphoglucose isomerase is the second enzyme in the glycolysis pathway, and its role is to convert glucose 6-phosphate into fructose 6-phosphate.
[6] In both of these cases, the tetrose is an inhibitor of an enzyme in the glycolysis pathway, preventing it from proceeding onward.