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Ribosomes mask cytochrome b5 on rough microsomal vesicles
Cell Biochemistry and Function
|June 24, 1998
Summary
Cytochrome b5 is exposed when ribosomes detach from rat liver microsomes. Re-attaching ribosomes covers this enzyme, suggesting its role in ribosome binding or protein synthesis.
Area of Science:
- Biochemistry
- Cell Biology
- Molecular Biology
Background:
- Rat liver microsomes contain cytochrome b5, a haemoprotein.
- Ribosomes are typically associated with the endoplasmic reticulum membranes.
Purpose of the Study:
- To investigate the localization and potential function of cytochrome b5 in rat liver microsomes.
- To determine the relationship between ribosome attachment and cytochrome b5 accessibility.
Main Methods:
- Chemical degranulation of rat liver microsomes to remove ribosomes.
- Re-attachment of ribosomes to stripped microsomal membranes.
- Assessing the accessibility of cytochrome b5 before and after ribosome manipulation.
Main Results:
- Cytochrome b5 is masked when ribosomes are attached to microsomal membranes.
- Chemical removal of ribosomes unmasks cytochrome b5.
- Re-attachment of ribosomes re-masks cytochrome b5 on the membrane surface.
Conclusions:
- Cytochrome b5's accessibility is regulated by ribosome binding to microsomal membranes.
- Cytochrome b5 may play a role in either ribosome-membrane attachment or protein biosynthesis by membrane-bound ribosomes.