What the work claims
Glycogen metabolism proceeds via a defined biochemical cycle involving lactic acid and reversible glucose 1-phosphate formation. Enzyme defects directly cause inherited human disease.
How it was done
They studied frog muscle tissue to identify an intermediate compound in glycogen breakdown. They isolated glucose 1-phosphate, determined its structure, identified phosphorylase as the enzyme that forms it, and demonstrated its reversibility. Gerty Cori examined human glycogen storage diseases, linking clinical phenotypes to specific enzymatic defects.
What holds up
The Cori cycle — glycogen → lactic acid in muscle, then resynthesis in liver — is established. Glucose 1-phosphate is confirmed as a reversible intermediate. Phosphorylase is identified as its catalysing enzyme. At least four glycogen storage disease forms are linked to specific enzymatic defects. Enzyme deficiency as cause of human genetic disease is demonstrated.
What does not
The sources do not report proof of causality beyond enzyme–disease linkage in glycogen storage diseases. They do not describe molecular mechanisms of enzyme defects, genetic inheritance patterns, or therapeutic interventions. No replication, consensus, or refutation is mentioned.
Why it matters beyond the lab
It established the first direct causal link between a human genetic disease and a specific enzyme defect — founding the field of inborn errors of metabolism. It made glycogen metabolism experimentally tractable, enabling later work on insulin signalling, diabetes therapeutics, and exercise physiology.
Is it worth your time
Yes. It redefined how metabolism is understood mechanistically — not as a black box but as a sequence of defined chemical steps with identifiable enzymes and intermediates. The work remains foundational for endocrinology, metabolic genetics, and pharmacology.