 Glycolytic intermediates can be diverted toward the non-oxidative phase of PPP by the expression of the gene for pyruvate kinase isozyme, PKM.PKM creates a bottleneck in the glycolytic pathway, allowing intermediates to be utilized by the PPP to synthesize NADPH and R5P.This process is further enabled by triosephosphate isomerase inhibition by phosphoenolpyruvate, the PKM substrate.