title: The separation and properties of two phosphoprotein phosphatases from the dimorphic fungus Mucor rouxii.
abstract: Soluble preparations from mycelium of the dimorphic fungus Mucor rouxii contained detectable amounts of phosphoprotein phosphatase activity. This cytosolic phosphatase activity exhibited a molecular weight below 80,000 and could be resolved into two different forms (enzymes I and II) by chromatography on DEAE-cellulose followed by gel filtration on Sephacryl S-300. Enzyme I (Mr 64,000) was mainly a histone phosphatase activity, absolutely dependent on divalent cations, with a K0.5 for MnCl2 of 2mM. Enzyme II (Mr 40,000) was active with histone and phosphorylase. Its activity was independent or slightly inhibited by Mn2+. This enzyme was strongly inhibited by 50 mM NaF or 1 mM ATP. When partially purified enzymes I and II were separately treated with ethanol, the catalytic properties of enzyme II were apparently not affected while those of enzyme I were drastically changed. The activity with histone, which was originally dependent on Mn2+, became independent or slightly inhibited by the cation. The treatment was accompanied by a notable increase in phosphorylase phosphatase activity which was strongly inhibited by Mn2+. Treated enzyme I eluted from DEAE-cellulose and Sephacryl S-300 columns at a position similar to that of enzyme II.
mesh_terms: D003600:Cytosol / Q000201:enzymology; D007700:Kinetics; D008345:Manganese / Q000494:pharmacology; D008970:Molecular Weight; D009089:Mucor / Q000201:enzymology*; D010749:Phosphoprotein Phosphatases / Q000302:isolation & purification* / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D008345:Manganese; D010749:Phosphoprotein Phosphatases