Abstract
A novel phosphorylation-dependent inhibitory protein (IP) of porcine aorta myosin light chain phosphatase (PA-MLCP) was purified to homogeneity from porcine aorta media. The molecular mass of IP was 20 kDa. IP phosphorylated by endogenous potentiating kinase (IP-K) inhibited not only PA-MLCP activity, but also that of the catalytic subunit of protein phosphatase-1. The amino acid sequence of a peptide derived from IP phosphorylated with IP-K, RHARVT*VK, shared one of the consensus sequences phosphorylatable by protein kinase C (PKC), where T* was phosphorylated. IP was phosphorylated by PKC and the phosphorylated product inhibited PA-MLCP as strongly as IP phosphorylated with IP-K.
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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Aorta / metabolism*
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Carrier Proteins*
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Chromatography
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Chromatography, Ion Exchange
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Durapatite
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Enzyme Inhibitors / isolation & purification
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Enzyme Inhibitors / metabolism
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Intracellular Signaling Peptides and Proteins*
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Kinetics
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Molecular Sequence Data
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Peptide Fragments / chemistry
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Peptide Fragments / isolation & purification
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Phosphoprotein Phosphatases / antagonists & inhibitors*
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Protein Kinase C / metabolism*
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Protein Phosphatase 1
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Proteins / chemistry
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Proteins / isolation & purification*
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Proteins / metabolism*
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Swine
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Tunica Media / metabolism*
Substances
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Carrier Proteins
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Enzyme Inhibitors
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Intracellular Signaling Peptides and Proteins
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Peptide Fragments
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Proteins
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protein phosphatase inhibitor-1
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Durapatite
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Protein Kinase C
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Phosphoprotein Phosphatases
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Protein Phosphatase 1