Metabolism of glycerate-2,3-P 2—III. Arginine-specific reagents inactivate the phosphoglycerate mutase, glycerate-2,3-P 2 synthase and glycerate-2,3-P 2 phosphatase activities of rabbit muscle phosphoglycerate mutase

Abstract

1. 1. Treatment of rabbit muscle phosphoglycerate mutase with diketones (2,3-butanedione and 1,2-cyclohexanedione) and with glyoxal derivatives (methylglyoxal and phenylglyoxal) produces the loss of the three activities of the enzyme: phosphoglycerate mutase, glycerate-2,3-P 2 synthase and glycerate-2,3-P 2 phosphatase. 2. 2. Hydroxylamine reactivates all the activities of the modified enzyme. 3. 3. Inactivated phosphoglycerate mutase is unable to form the functionally active phosphoenzyme when mixed with glycerate-2,3-P 2. 4. 4. Both substrate and cofactor protect against inactivation. 5. 5. These results provide additional evidence of the intrinsic character of the three enzymatic activities of phosphoglycerate mutase and favor their location at the same active site. 6. 6. In addition, they suggest that arginine is involved in the binding of the cofactor to the enzyme.