Related Experiment Videos
Effects of various ligands on interaction of AMP deaminase with myosin
Abstract:
Purified rat muscle AMP deaminase (AMP aminohydrolase, EC 3.5.4.6) binds tightly to rat myosin. The binding is abolished in the presence of low concentrations of various ligands. Pyrophosphate and GTP at concentrations as low as 0.1 micrometer were effective in abolishing the interaction between two proteins. Other nucleoside triphosphates were less effective than GTP and the concentrations required for 50% inhibition were approximately 0.3 to 0.7 micrometer. ADP and AMP are effective in inhibiting the interaction between two proteins, but they are less effective than the nucleoside triphosphates; 50% inhibition occurred at 34 micrometer with ADP and at 1 mM with AMP. Creatine phosphate and inorganic phosphate showed 50% inhibition at 5 to 6 mM. All of the compounds, which affected AMP deaminase activity, were effective in abolishing the interaction of the enzyme with myosin; however, the interaction-abolishing effects of the compounds are not parallel with their inhibitory effects on the deaminase activity. Although there exist three parental isozymes of AMP deaminase in the rat, all three enzymes interacted with myosin.
Insights
Rat muscle AMP deaminase binds to myosin, but this interaction is disrupted by ligands like pyrophosphate and GTP. These compounds affect binding differently than they affect enzyme activity.
Area of Science:
- Biochemistry
- Molecular Biology
- Enzymology
Background:
- AMP deaminase (AMP aminohydrolase, EC 3.5.4.6) is a key enzyme in purine metabolism.
- Muscle AMP deaminase plays a role in energy homeostasis.
- The interaction between AMP deaminase and myosin is not well understood.
Purpose of the Study:
- To investigate the binding interaction between purified rat muscle AMP deaminase and rat myosin.
- To identify ligands that modulate this protein-protein interaction.
- To compare the effects of ligands on binding versus enzymatic activity.
Main Methods:
- Purification of rat muscle AMP deaminase.
- Co-incubation of purified AMP deaminase with myosin.
- Assay of protein binding in the presence of various ligands.
- Measurement of AMP deaminase enzymatic activity.
Main Results:
- Purified rat muscle AMP deaminase binds tightly to rat myosin.
- Ligands such as pyrophosphate and GTP effectively abolish this binding at low concentrations (0.1 µM).
- Other nucleoside triphosphates, ADP, AMP, creatine phosphate, and inorganic phosphate also inhibit the interaction, but with varying potencies.
- All tested compounds that affected AMP deaminase activity also abolished its interaction with myosin, though not in parallel with their inhibitory effects on deaminase activity.
- All three parental isozymes of rat AMP deaminase interacted with myosin.
Conclusions:
- Rat muscle AMP deaminase exhibits specific binding to myosin.
- This interaction is modulated by various ligands, including nucleoside triphosphates and phosphates.
- The affinity of ligands for disrupting AMP deaminase-myosin binding differs from their effects on AMP deaminase enzymatic activity.
- All AMP deaminase isozymes in rats interact with myosin.