Assessment of protein turnover by use of radioisotopic tracers
The principles of chemical kinetics were applied to turnover studies soon after tracers had been introduced into biological experiments, and several reviews on this subject are available. However, rigorous precursor-product analysis of protein turnover was seldom attempted in the past, mostly because it was assumed that the radioactive precursors of proteins are rapidly eliminated from the organisms. The estimate of protein half-life therefore was based on measurements of decay of the protein radioactivity only. Although such experiments clearly confirmed the dynamic state of protein molecules, it was later recognized that this approach leads to a gross overestimate of protein half-lives because the tracer amino acids are not eliminated as fast as had been thought. The omission of precursor specific radioactivity in calculations of turnover rates thus is not justified. Consequently, any meaningful measure of protein turnover requires determination of the specific radioactivity of the amino acid, both in the protein molecule and in the precursor pool.
- Research Organization:
- Univ. of Chicago, IL
- OSTI ID:
- 7032013
- Journal Information:
- Physiol. Rev.; (United States), Journal Name: Physiol. Rev.; (United States) Vol. 59:2; ISSN PHREA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL HALF-LIFE
BIOLOGICAL PATHWAYS
BIOSYNTHESIS
CARBOXYLIC ACIDS
DYNAMIC FUNCTION STUDIES
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
METABOLISM
ORGANIC ACIDS
ORGANIC COMPOUNDS
PRECURSOR
RADIONUCLIDE KINETICS
REACTION KINETICS
SYNTHESIS
TRACER TECHNIQUES