Glycolysis and the HMS. Enzyme activities are indicated by arrows. Important enzymes shown here are hexokinase, glucose-6-phosphate dehydrogenase (G-6-PDase), phosphofructokinase (PFK), pyruvate kinase (PK), and lactate dehydrogenase (LDH). The substrates listed here are: glucose-6-phosphate (G-6-P), phosphoenolpyruvate (PEP), and glyceraldehyde 3-phosphate (GA3P).