Question: why is hmp inactive in muscles?
Answer: As a energy molecule. 9. IN THE MUSCLE  HMP Shunt inactive because G 6P Dehydrogenase and 6 P Gluconate Dehydrogenase deficient So they act as checkers for NADPH production.  ribose 5 P synthesized in the way of reverse HMP Shunt or through Transketolase path.