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NAD kinase interaction with the activator--glutamate dehydrogenase
V I Telepneva1, O L Voronina, E R Bulygina
1Department of Biochemistry, School of Biology, Moscow State University, USSR.
Biochemistry International
|May 1, 1987
Summary
Researchers identified a NAD kinase activating factor from rabbit liver as glutamate dehydrogenase. This enzyme forms complexes with both oligomeric and monomeric forms of NAD kinase, revealing a new regulatory interaction.
Area of Science:
- Biochemistry
- Enzymology
- Molecular Biology
Background:
- NAD kinase is a crucial enzyme in NADP+ biosynthesis.
- Regulation of NAD kinase activity is essential for cellular metabolism.
- A specific activating factor for NAD kinase was previously identified in rabbit liver.
Purpose of the Study:
- To isolate and characterize the NAD kinase activating factor from rabbit liver.
- To identify the molecular identity of the NAD kinase activating factor.
- To investigate the interaction between the activating factor and NAD kinase.
Main Methods:
- Electrophoretic isolation of the activating factor.
- Physicochemical property analysis (molecular weight, pI, SH-groups).
- Enzyme activity assays and complex formation studies using three independent methods.
Main Results:
- The NAD kinase activating factor was purified to electrophoretic homogeneity from rabbit liver.
- Physicochemical properties strongly indicated the factor is glutamate dehydrogenase.
- Glutamate dehydrogenase demonstrated NAD kinase activating activity.
- Complex formation between NAD kinase and glutamate dehydrogenase was confirmed.
- Both oligomeric and monomeric NAD kinase formed complexes with glutamate dehydrogenase.
Conclusions:
- The NAD kinase activating factor is identified as glutamate dehydrogenase.
- Glutamate dehydrogenase directly interacts with and activates NAD kinase.
- This interaction involves both forms of NAD kinase, suggesting a novel regulatory mechanism.