Phosphoglucomutase catalytic reaction

Leloir110(a) has described a conversion of D-mannosyl phosphate to D-mannose 6-phosphate by phosphoglucomutase, and here, too, the reaction requires catalytic quantities of a-D-glucose 1,6-diphosphate. The role of the latter is probably to generate a-D-mannose 1,6-diphosphate as follows. 

Experimental Determination of K eq and AG ° If a 0.1 M solution of glucose 1-phosphate at 25 °C is incubated with a catalytic amount of phosphoglucomutase, the glucose 1-phosphate is transformed to glucose 6-phosphate. At equilibrium, the concentrations of the reaction components are... 

The involvement of methionine sulfonium salts in these chemical cleavage reactions may stimulate experiments to show the significance of special methionine residues in the active centers and the catalytic sites of enzymes. Such an important role for a particular methionine has been postulated for the enzymes phosphoglucomutase and chymotrypsin on the basis of photooxidation studies (Ray et al., 1960). 

Only catalytic amounts of the diphosphates are required for the reaction. The phosphoglucomutase also acts on D-mannose phosphate and D-ribose phosphate and is thought to catalyze the interconversion of D-mannose 1-phosphate to D-mannose 6-phosphate and D-ribose 1-phosphate to D-ribose... 

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