title: Purification and characterization of the polycation-stimulated protein phosphatase catalytic subunit from porcine renal cortex.
abstract: The predominant form of phosphorylase phosphatase activity in porcine renal cortical extracts was a polycation-stimulated protein phosphatase. This activity was present in extracts in a high-molecular-weight form which could be converted to a free catalytic subunit by treatment with ethanol, urea, or freezing and thawing in the presence of beta-mercaptoethanol. The catalytic subunit of the polycation-stimulated phosphatase was purified by chromatography on DEAE-Sephacel, heparin-Sepharose, and Sephadex G-75. The phosphatase appeared to be homogeneous on SDS-polyacrylamide gel electrophoresis. The enzyme had an apparent Mr of 35 000 on gel filtration and SDS-polyacrylamide gel electrophoresis. The purified phosphatase could be stimulated by histone H1, protamine, poly(D-lysine), poly(L-lysine) or polybrene utilizing phosphorylase a as the substrate. It preferentially dephosphorylated the alpha-subunit of phosphorylase kinase. The phosphatase was highly sensitive to inhibition by ATP. These results suggest that the renal polycation-stimulated phosphatase catalytic subunit is very similar to or identical with the skeletal muscle phosphatase form which has been previously designated phosphatase-2Ac.
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D000431:Ethanol / Q000494:pharmacology; D005615:Freezing; D006583:Hexadimethrine Bromide / Q000494:pharmacology; D006657:Histones / Q000494:pharmacology; D007672:Kidney Cortex / Q000201:enzymology*; D046911:Macromolecular Substances; D008623:Mercaptoethanol / Q000494:pharmacology; D008970:Molecular Weight; D010749:Phosphoprotein Phosphatases / Q000302:isolation & purification*; D010766:Phosphorylation; D013552:Swine; D014508:Urea / Q000494:pharmacology
chemical_list: D006657:Histones; D046911:Macromolecular Substances; D000431:Ethanol; D006583:Hexadimethrine Bromide; D008623:Mercaptoethanol; D000255:Adenosine Triphosphate; D014508:Urea; D010749:Phosphoprotein Phosphatases