Which stage of the Hexose Monophosphate (HMP) pathway depends on thiamine pyrophosphate (TPP)?

Explanation

In the HMP pathway, the enzyme transketolase requires thiamine pyrophosphate (TPP) as a cofactor to catalyze the transfer of two-carbon units. Other enzymes such as glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase do not require TPP.