Glucose Diphosphate and Diphosphoglyceric Acid

The coenzymes of the phosphomutases (glucose diphosphate and diphosphoglyceric acid) are a recently discovered group of coenzymes which 

Colowick, and Cori were the first to study the phosphoglucomutase reaction, and they demonstrated the widespread occurrence of this enzyme in animal tissues and in yeast. The muscle enzyme was finally crystallized by Najjar. Leloir and his co-workers proved the 

The structure of the coenzyme is given in Fig. 6. The coenzyme is a nonreducing substance. Heating in 0.1 N hydrochloric acid at 100 for 10 min. hydrolyzes the labile 1-phosphate group and destroys biological activity. One equivalent of aldose is formed per mole of phosphate split off. Glucose-6-phosphate was shown to be the remaining product. 

After a second lead precipitation, a barium precipitation is followed by an acetone precipitation of the barium-free product. The coenzyme is finally isolated as a water-insoluble barium salt at pH 8. 

The coenzyme is the a isomer of glucose diphosphate. Its synthesis has been achieved by Posternak in the following manner j3-l-Bromo-2,3,4-triacetyl-6-diphenylphosphonoglucose is reacted with silver diphenylphos-phate. The product, upon removal of the phenyl and acetyl groups, yields the coenzyme. 

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