The separation and properties of two phosphoprotein phosphatases from the dimorphic fungus Mucor rouxii.
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.
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
D008345:Manganese; D010749:Phosphoprotein Phosphatases