Related Experiment Videos
The microtubule-associated nucleoside diphosphate kinase
The Journal of Biological Chemistry
|September 25, 1984
Summary
Researchers isolated a nucleoside diphosphate kinase (NDP kinase) enzyme from microtubule protein. This enzyme, a hexamer, copurifies with microtubules and may play a role in their assembly regulation.
Area of Science:
- Biochemistry
- Cell Biology
- Neuroscience
Background:
- Microtubule protein preparations exhibit nucleoside diphosphate kinase (NDP kinase) activity.
- The specific NDP kinase responsible for this activity was not previously identified.
Purpose of the Study:
- To isolate and characterize the NDP kinase associated with microtubule protein.
- To investigate the potential role of this NDP kinase in microtubule assembly.
Main Methods:
- Isolation of NDP kinase from twice-polymerized bovine brain microtubule protein using a five-step chromatographic procedure.
- Determination of molecular weight via sedimentation equilibrium.
- Analysis of subunit composition using SDS-PAGE and silver staining.
- Comparison of enzyme isolated from microtubule protein with whole-brain NDP kinase.
Main Results:
- A hexameric NDP kinase with subunits of approximately 18,000 daltons was isolated.
- The isolated enzyme exhibited similar properties (isozyme, kinetics, thermal stability) to NDP kinase purified directly from whole bovine brain.
- Both subunits of NDP kinase could be reversibly phosphorylated by ATP, generating active, more acidic forms.
Conclusions:
- The NDP kinase isolated from microtubule protein is likely identical to the enzyme found throughout the brain.
- This enzyme's ability to copurify with microtubules facilitates further research into its function in microtubule assembly and regulation.