TY - JOUR
T1 - Purification and characterization of a phosphoprotein phosphatase from bovine adrenal cortex
AU - Ullman, Buddy
AU - Perlman, Robert L.
N1 - Funding Information:
This investigation was supported by Research Grant AM 15135 from the National Institutes of Health. R.L.P. is the recipient of a Research Career Development Award, AM 70648, from the National Institutes of Health. We thank Ms Michele Carvotta for expert technical assistance.
PY - 1975/10/22
Y1 - 1975/10/22
N2 - A phosphoprotein phosphatase which is active against chemically phosphorylated protamine has been purified about 500-fold from bovine adrenal cortex. The enzyme has a pH optimum between 7.5 and 8.0 and has an apparent Km for phosphoprotamine of about 50 μM. The hydrolysis of phosphoprotamine is stimulated by salt, and by Mn2+. Hydrolysis of phosphoprotamine is inhibited by ATP, ADP, AMP, Pi, but is not affected by AMP or cyclic GMP. The purified phosphoprotein phosphatase preparation also dephosphorylates p-nitrophenyl phosphate and phosphohistone, and catalyzes the inactivation of liver phosphorylase, the inactivation of muscle phosphorylase a (and its conversion to phosphorylase b), and the inactivation of muscle phosphorylase b kinase. Phosphatase activities against phosphoprotamine and muscle phosphorylase a copurify over the last three stages of purification. Phosphoprotamine inhibits phosphorylase phosphatase activity, and muscle phosphorylase a inhibits the dephosphorylation of phosphoprotamine. These results suggest that one enzyme possesses both phosphoprotamine phosphatase and phosphorylase phosphatase activities. The stimulation of phosphorylase phosphatase activity, but not of phosphoprotamine phosphatase activity, by caffeine and by glucose, suggest that the different activities of this phosphoprotein phosphatase may be regulated separately.
AB - A phosphoprotein phosphatase which is active against chemically phosphorylated protamine has been purified about 500-fold from bovine adrenal cortex. The enzyme has a pH optimum between 7.5 and 8.0 and has an apparent Km for phosphoprotamine of about 50 μM. The hydrolysis of phosphoprotamine is stimulated by salt, and by Mn2+. Hydrolysis of phosphoprotamine is inhibited by ATP, ADP, AMP, Pi, but is not affected by AMP or cyclic GMP. The purified phosphoprotein phosphatase preparation also dephosphorylates p-nitrophenyl phosphate and phosphohistone, and catalyzes the inactivation of liver phosphorylase, the inactivation of muscle phosphorylase a (and its conversion to phosphorylase b), and the inactivation of muscle phosphorylase b kinase. Phosphatase activities against phosphoprotamine and muscle phosphorylase a copurify over the last three stages of purification. Phosphoprotamine inhibits phosphorylase phosphatase activity, and muscle phosphorylase a inhibits the dephosphorylation of phosphoprotamine. These results suggest that one enzyme possesses both phosphoprotamine phosphatase and phosphorylase phosphatase activities. The stimulation of phosphorylase phosphatase activity, but not of phosphoprotamine phosphatase activity, by caffeine and by glucose, suggest that the different activities of this phosphoprotein phosphatase may be regulated separately.
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U2 - 10.1016/0005-2744(75)90068-6
DO - 10.1016/0005-2744(75)90068-6
M3 - Article
C2 - 241403
AN - SCOPUS:0016715849
SN - 0005-2744
VL - 403
SP - 393
EP - 411
JO - BBA - Enzymology
JF - BBA - Enzymology
IS - 2
ER -