Discussion:
Low levels of metabolite
A child approaches you complaining of progressive muscle weakness and inability to keep up with friends in athletic endeavors. You decide to take a muscle biopsy and send a sample out for analysis of some key metabolites. You receive back the following data. (You can neglect units; simply compare the patient's values with the normal values.)
Level of Indicated Metabolite in Muscle of:
Patient Normal controls
Glycogen 50 10
Glucose 6-phosphate 10 1
Fructose 6-phosphate 2.0 0.1
Fructose 1,6-bisphosphate 0.01 1.0
1. Which enzyme is most likely deficient in the patient's muscle?
2. Why did you conclude that this enzyme is deficient?
3. Why does deficiency of this enzyme lead to the clinical symptoms described by the patient?