D-Glucose 1-Phosphate Cori Ester

This ester was first isolated as a crude product by Cori, Colowick, and Cori 218) as a result of the action of frog muscle enzymes on glycogen and inorganic phosphate. A pure product was obtained when rabbit muscle extracts were dialyzed and then incubated with glycogen, phosphate buffer, and adenylic acid. The latter served as an activator of the enzyme (phos-phorylase). 

Since the ester is alkali-stable and non-reducing and liberates D-glucose on hydrolysis, the phosphate must be attached to carbon 1 in the D-glu-cose. Cori, Colowick, and Cori 218) suggested that the hexose phosphate 

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