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Processing mechanisms in the biosynthesis of proteins
Annals of the New York Academy of Sciences
|January 1, 1980
Summary
Limited proteolysis is crucial for protein biosynthesis, involving precursor cleavage. Presecretory proteins, like proinsulin, are processed via specific enzymatic mechanisms during synthesis and maturation.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- Limited proteolysis is a fundamental mechanism in protein biosynthesis.
- Protein precursors are diverse, varying in function, cellular localization, and cleavage pathways.
- Presecretory proteins are rapidly processed during synthesis, linked to ribosome-membrane structures.
Purpose of the Study:
- To classify protein precursors based on function, localization, and cleavage.
- To propose a model for presecretory protein processing at the ribosome-membrane junction.
- To illustrate the post-translational processing of proproteins like proinsulin.
Main Methods:
- Classification of protein precursors.
- Proposed model of prepeptide interaction with microsomal membranes.
- Analysis of post-translational processing pathways for various proproteins.
Main Results:
- Presecretory proteins are cleaved early in synthesis, associated with ribosome-membrane structures.
- A model suggests prepeptide beta-pleated sheet formation with membrane components.
- Proproteins undergo post-translational cleavage within secretory cells or extracellularly.
Conclusions:
- Limited proteolysis is essential for generating functional proteins from precursors.
- Diverse mechanisms exist for protein precursor processing, both intracellularly and extracellularly.
- Understanding these pathways is key to comprehending protein biosynthesis and function.