Purification and properties of phosphoglyceromutase from sheep muscle.
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Phosphoglyceromutase (2,3-diphospho-D-glycerate phosphotransferase, EC 2.7.5.3) has been purified from sheep muscle. The enzyme has a specific activity of 828 units/mg and is stable for several months at 0–2 °C in 0.1 μ phosphate buffer, pH 7.0. The Km for 2,3-diphosphoglycerate (DPGA) is 0.003 mM; the Km for 3-phosphoglycerate is 9.0 mM. A small amount of DPGA-phosphatase activity was associated with the enzyme.At pH 5.4 and 7.0 sheep phosphoglyceromutase was shown to be homogeneous by sedimenting as a single sharp peak in the ultracentrifuge and by the appearance of a single band on both disc gel and cellulose acetate electrophoresis. The sedimentation coefficient of the enzyme at pH 7.0 was 4.1 S, the diffusion constant 7.21 × 10−7 cm2/s, and the molecular weight calculated from both the-sedimentation and gel filtration data was of the order of 51 000.Disc gel electrophoresis of the enzyme at pH 9.3 revealed the presence of three protein components which were shown to be charge isomers.Titration of the...