What is a protein half-life?

The half-life of a protein is defined as the time it takes for the concentration of the radiolabeled target protein to be reduced by 50\% relative to the level at the beginning of the chase. Another method to determine the turnover rate of a given protein is referred to as cycloheximide blocking.

How long is a protein half-life?

The median half-life is 7.1 hours and the majority of proteins have half-lives less than 8 hours. There have already been several reports regarding the measurement of protein half-lives by using SILAC-based pulse-chase combined with MS-based proteomics.

How is protein half-life determined?

Two methods are commonly used to determine a protein’s half-life, namely radioactive pulse-chase analysis and cycloheximide chase (2). Pulse-chase analysis provides minimal distortion of normal cell physiology. Since 2002, a number of so-called photoactivatable fluorescent proteins (PAFPs) have been developed (7).

How do you determine the half life of a protein?

Two methods are commonly used to determine a protein’s half-life, namely radioactive pulse-chase analysis and cycloheximide chase (2). Pulse-chase analysis provides minimal distortion of normal cell physiology. The main disadvantages of this method are its laboriousness and necessity for radiolabeling.

Why is it important for some proteins to have a short half-life but not others?

Some proteins have very short half-lives because they are specifically targeted for degradation. Abnormal proteins are also selectively hydrolyzed. The pathway for the selective hydrolysis of these proteins in eukaryotic cells requires the protein ubiquitin.

What is the half-life of a cell?

Assaying 100 proteins in living human cancer cells showed half-lives that ranged between 45 minutes and 22.5 hours. A variety of stresses that stop cell division showed the same general effect: Long-lived proteins became longer-lived, whereas short-lived proteins remained largely unaffected.