Phosphoglycerate mutase from wheat germ: studies with 18O-labeled substrate, investigations of the phosphatase and phosphoryl transfer activities, and evidence for a phosphoryl-enzyme intermediate.
From studies using unlabeled phospho-D-glycerate in solutions enriched in H2(18)O, and from experiments involving [18O]phospho-D-glycerate, it is shown that the intramolecular isomerization of 2- and 3-phospho-D-glycerate that is catalyzed by the phosphoglycerate mutase from wheat germ does not involve an intermediate 2,3-cyclic phosphate. It is also shown that phosphoglycerate mutase catalyzes the hydrolysis of the substrate analogues 2-phosphoglycolate, 2-phospho-D-lactate, 3-phosphohydroxypropionate, phosphoenolpyruvate, and phosphohydroxypyruvate. The substrates 3- and 2-phospho-D-glycerate are not hydrolyzed, nor are 2,3-bisphospho-D-glycerate, 2-phospho-L-lactate, 3-phospho-L-glycerate, or sn-glycerol 3-phosphate. Although no exchange of D-[14C]glycerate into phospho-D-glycerate can be detected, the enzyme catalyzes the transfer of the phosphoryl group from "unnatural" donors such as 2-phosphoglycolate, to the "natural" acceptor, D-glycerate. It is concluded that the intramolecular phosphoryl transfer catalyzed by the wheat germ phosphoglycerate mutase follows a pathway involving a phosphoryl-enzyme intermediate.
D005994:Glycerophosphates / Q000096:biosynthesis*; D007700:Kinetics; D013058:Mass Spectrometry; D010736:Phosphoglycerate Mutase / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D010770:Phosphotransferases / Q000378:metabolism*; D013329:Structure-Activity Relationship; D014908:Triticum
D005994:Glycerophosphates; D010750:Phosphoproteins; D010770:Phosphotransferases; D010744:Phosphoric Monoester Hydrolases; D010736:Phosphoglycerate Mutase