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Characterize the purification, protein kinase-mediated phosphorylation, and regulatory properties of calmodulin-dependent phosphodiesterase isolated from bovine heart tissue.

June 1, 1991Biochemistry

Phosphorylation and characterization of bovine heart calmodulin-dependent phosphodiesterase

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Characterize the purification, protein kinase-mediated phosphorylation, and regulatory properties of calmodulin-dependent phosphodiesterase isolated from bovine heart tissue.
Purified calmodulin-dependent phosphodiesterase to apparent homogeneity from the bovine heart calmodulin-binding fraction using single-step immunoaffinity chromatography.
Assayed phosphorylation kinetics using cAMP-dependent protein kinase in the presence and absence of histidine, followed by dephosphorylation with calcineurin.
Determined calcium concentration requirements for 50% enzymatic activation in phosphorylated versus nonphosphorylated phosphodiesterase at 650 nM calmodulin.
cAMP-dependent protein kinase catalyzed the stoichiometric phosphorylation of cardiac phosphodiesterase (1 mol phosphate per mol subunit), with the phosphorylation rate enhanced severalfold by histidine.
Phosphorylation reduced enzymatic affinity for calcium and calmodulin, shifting the calcium requirement for 50% activity from 0.8 µM in nonphosphorylated enzyme to 20 µM in phosphorylated enzyme at 650 nM calmodulin.
Calmodulin-dependent phosphatase (calcineurin) completely reversed phosphorylation, which restored the high affinity of phosphodiesterase for calmodulin.

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Implication

In vitro biochemical analysis demonstrates reversible phosphorylation of cardiac calmodulin-dependent phosphodiesterase, indicating cross-talk between cAMP and calcium signaling pathways.

Cite This Study

R. K. Sharma (1991) studied this question.

synapsesocial.com/papers/6aaa1055d33e8d464755830c https://doi.org/10.1021/bi00238a021

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Implication

In vitro biochemical analysis demonstrates reversible phosphorylation of cardiac calmodulin-dependent phosphodiesterase, indicating cross-talk between cAMP and calcium signaling pathways.

Phosphorylation and characterization of bovine heart calmodulin-dependent phosphodiesterase

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Discussion

Implication

Cite This Study

Phosphorylation and characterization of bovine heart calmodulin-dependent phosphodiesterase

Key Points

Discussion

Implication

Cite This Study

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