Abstract
The glycogen-binding (G) subunit of protein phosphatase-1 is phosphorylated in vivo. In rabbits injected with propranolol the serine residue termed site-1 was phosphorylated in 56% of the molecules isolated, and phosphorylation increased to 82% after administration of adrenalin. It is concluded that the G-subunit is a physiological substrate for cyclic AMP-dependent protein kinase. The G-subunit remained largely bound to glycogen even after injection of adrenalin, whereas half of the protein phosphatase-1 activity associated with glycogen was released into the cytosol. The results indicate that adrenalin induces dissociation of the catalytic subunit from the G-subunit in vivo.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Chromatography, Gel
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Chromatography, High Pressure Liquid
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Cyclic AMP / pharmacology
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Cytosol / enzymology
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Epinephrine / pharmacology*
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Glycogen / metabolism*
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Glycogen-Synthase-D Phosphatase / metabolism*
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Mass Spectrometry
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Molecular Sequence Data
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Muscles / drug effects
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Muscles / enzymology*
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Peptide Fragments
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Phosphoprotein Phosphatases / metabolism*
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Phosphorylation
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Phosphoserine / metabolism
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Propranolol / pharmacology
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Protein Kinases / metabolism
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Protein Phosphatase 1
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Rabbits
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Trypsin
Substances
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Peptide Fragments
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Phosphoserine
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Glycogen
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Propranolol
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Cyclic AMP
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Protein Kinases
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Phosphoprotein Phosphatases
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Protein Phosphatase 1
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Glycogen-Synthase-D Phosphatase
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Trypsin
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Epinephrine