The properties of purified low molecular weight phosphoprotein phosphatase from rabbit heart.
A simplified procedure for the purification of low molecular weight phosphoprotein phosphatase acting on muscle phosphorylase a has been described from rabbit heart. The enzyme was purified to homogeneity by acid precipitation, ethanol treatment, and chromatography on Sephadex G-75 and Sepharose-histone. The purified enzyme showed a single band when examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis; the molecular weight calculated by this method was 34 000. The S20, W value and Stokes radius for the enzyme was 3.35 and 24.0 A(1 A = 0.1 nm), respectively. Using these two values, a molecular weight of 35 000 was calculated. Purified enzyme showed a wide substrate specificity and catalyzed the dephosphorylation of phosphorylase a, glycogen synthase D, phosphorylated histone, and phosphorylated casein. Kinetic studies revealed the lowest Km with glycogen synthase D and maximum Vmax for the reaction with phosphorylase a.
D000645:Ammonium Sulfate; D000818:Animals; D002847:Chromatography, Agarose; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D008970:Molecular Weight; D009206:Myocardium / Q000201:enzymology*; D010749:Phosphoprotein Phosphatases / Q000302:isolation & purification*; D011817:Rabbits; D012967:Sodium Dodecyl Sulfate; D013379:Substrate Specificity
D012967:Sodium Dodecyl Sulfate; D010749:Phosphoprotein Phosphatases; D000645:Ammonium Sulfate