title: Dissociation of phosphohistone phosphatases from canine heart.
abstract: Phosphohistone phosphatase (phosphoprotein phosphohydrolase, EC 3.1.3.16) of canine heart extract has been separated by DEAE-cellulose chromatography into 4 molecular forms, namely phosphatases A (Mr = 156 000), B (Mr = 161 000), C (Mr = 95 600) and U (Mr = 61 000). ATP inhibited phosphatase A, stimulated phosphatase B and did not significantly affect phosphatase C activity. Phosphatase U requires Mn2+ for activity, under which condition ATP is inhibitory. Phosphatases A, B and C, but not phosphatase U, were dissociated by ethanol into catalytic subunits that were inhibited by ATP, insensitive to Mn2+, and had a common molecular weight of 34 800 (phosphatase S). The dissociation was accompanied by an increase of enzymic activity. Chromatography of the ethanol-treated 55% (NH4)2SO4 fraction of canine heart extract on DEAE-cellulose demonstrated that the multiple forms of phosphohistone phosphatase could be reduced to two forms: phosphatase U and phosphatase S, which may represent two basic constituents of the multiple forms of phosphohistone phosphatase in canine heart.
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D004285:Dogs; D000431:Ethanol; D046911:Macromolecular Substances; D008345:Manganese / Q000494:pharmacology; D008970:Molecular Weight; D009206:Myocardium / Q000201:enzymology*; D010750:Phosphoproteins; D010744:Phosphoric Monoester Hydrolases / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D046911:Macromolecular Substances; D010750:Phosphoproteins; D000431:Ethanol; D008345:Manganese; D000255:Adenosine Triphosphate; D010744:Phosphoric Monoester Hydrolases