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Hormone-receptor studies with avidin and biotinylinsulin-avidin complexes
The Journal of Biological Chemistry
|June 25, 1980
Summary
Modified avidin (pHPP-avidin) allows for high-specific-radioactivity labeling. Succinoylated pHPP-avidin (SpHPP-avidin) reduces nonspecific binding, enabling specific hormone-receptor interactions for potential new labeling techniques.
Area of Science:
- Biochemistry
- Molecular Biology
- Radiochemistry
Background:
- Avidin labeling is crucial for various biochemical assays.
- High specific radioactivity is desirable for sensitive detection.
- Unmodified avidin can lead to anomalous binding behaviors in assays.
Purpose of the Study:
- To develop a method for high-specific-radioactivity labeling of avidin.
- To improve the specificity of avidin binding to biological membranes.
- To explore a novel technique for labeling peptide hormones.
Main Methods:
- Introduction of 3-(p-hydroxyphenyl)-propionyl groups (pHPP) to avidin.
- Succoylation of pHPP-avidin with succinic anhydride (SpHPP-avidin).
- Binding studies using radiolabeled avidin derivatives and biotinyl-insulin with rat liver plasma membranes.
Main Results:
- 125I-pHPP-avidin binds avidly to rat liver plasma membranes.
- Succinoylation significantly reduces nonspecific binding of labeled avidin.
- Biotinylinsulin complexes with SpHPP-avidin show specific and saturable binding to receptors.
Conclusions:
- The biotinylhormoneSpHPP-avidin technique offers a promising method for labeling peptide hormones.
- This technique is particularly useful for compounds that are difficult to iodinate.
- Modified avidin derivatives provide enhanced specificity in binding assays.